diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/Block.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/Block.kt
new file mode 100644
index 00000000..a80ad2b7
--- /dev/null
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/Block.kt
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2024 usbharu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dev.usbharu.hideout.core.application.relationship
+
+data class Block(val targetActorId: Long)
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/FollowRequest.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/FollowRequest.kt
new file mode 100644
index 00000000..eb61df82
--- /dev/null
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/FollowRequest.kt
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2024 usbharu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dev.usbharu.hideout.core.application.relationship
+
+data class FollowRequest(val targetActorId: Long)
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/GetRelationship.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/GetRelationship.kt
new file mode 100644
index 00000000..c040253b
--- /dev/null
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/GetRelationship.kt
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2024 usbharu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dev.usbharu.hideout.core.application.relationship
+
+data class GetRelationship(val targetActorId: Long)
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/GetRelationshipApplicationService.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/GetRelationshipApplicationService.kt
new file mode 100644
index 00000000..9ba79ff3
--- /dev/null
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/GetRelationshipApplicationService.kt
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2024 usbharu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dev.usbharu.hideout.core.application.relationship
+
+import dev.usbharu.hideout.core.application.shared.AbstractApplicationService
+import dev.usbharu.hideout.core.application.shared.CommandExecutor
+import dev.usbharu.hideout.core.application.shared.Transaction
+import dev.usbharu.hideout.core.application.shared.UserDetailGettableCommandExecutor
+import dev.usbharu.hideout.core.domain.model.actor.ActorId
+import dev.usbharu.hideout.core.domain.model.actor.ActorRepository
+import dev.usbharu.hideout.core.domain.model.actorinstancerelationship.ActorInstanceRelationship
+import dev.usbharu.hideout.core.domain.model.actorinstancerelationship.ActorInstanceRelationshipRepository
+import dev.usbharu.hideout.core.domain.model.relationship.RelationshipRepository
+import dev.usbharu.hideout.core.domain.model.userdetails.UserDetailRepository
+import org.slf4j.LoggerFactory
+import org.springframework.stereotype.Service
+
+@Service
+class GetRelationshipApplicationService(
+    private val relationshipRepository: RelationshipRepository,
+    private val actorRepository: ActorRepository,
+    private val userDetailRepository: UserDetailRepository,
+    private val actorInstanceRelationshipRepository: ActorInstanceRelationshipRepository,
+    transaction: Transaction,
+) :
+    AbstractApplicationService<GetRelationship, Relationship>(
+        transaction, logger
+    ) {
+    companion object {
+        private val logger = LoggerFactory.getLogger(GetRelationshipApplicationService::class.java)
+    }
+
+    override suspend fun internalExecute(command: GetRelationship, executor: CommandExecutor): Relationship {
+        require(executor is UserDetailGettableCommandExecutor)
+        val userDetail = userDetailRepository.findById(executor.userDetailId)!!
+        val actor = actorRepository.findById(userDetail.actorId)!!
+        val targetId = ActorId(command.targetActorId)
+        val target = actorRepository.findById(targetId)!!
+        val relationship = (relationshipRepository.findByActorIdAndTargetId(actor.id, targetId)
+            ?: dev.usbharu.hideout.core.domain.model.relationship.Relationship.default(actor.id, targetId))
+
+        val relationship1 = (relationshipRepository.findByActorIdAndTargetId(targetId, actor.id)
+            ?: dev.usbharu.hideout.core.domain.model.relationship.Relationship.default(targetId, actor.id))
+
+        val actorInstanceRelationship =
+            actorInstanceRelationshipRepository.findByActorIdAndInstanceId(actor.id, target.instance)
+                ?: ActorInstanceRelationship.default(
+                    actor.id,
+                    target.instance
+                )
+
+        return Relationship.of(relationship, relationship1, actorInstanceRelationship)
+    }
+}
\ No newline at end of file
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/Relationship.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/Relationship.kt
new file mode 100644
index 00000000..c7b2377a
--- /dev/null
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/Relationship.kt
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2024 usbharu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dev.usbharu.hideout.core.application.relationship
+
+import dev.usbharu.hideout.core.domain.model.actorinstancerelationship.ActorInstanceRelationship
+import dev.usbharu.hideout.core.domain.model.relationship.Relationship
+
+data class Relationship(
+    val actorId: Long,
+    val targetId: Long,
+    val following: Boolean,
+    val followedBy: Boolean,
+    val blocking: Boolean,
+    val blockedBy: Boolean,
+    val muting: Boolean,
+    val followRequesting: Boolean,
+    val followRequestedBy: Boolean,
+    val domainBlocking: Boolean,
+    val domainMuting: Boolean,
+    val domainDoNotSendPrivate: Boolean,
+) {
+    companion object {
+        fun of(
+            relationship: Relationship,
+            relationship2: Relationship,
+            actorInstanceRelationship: ActorInstanceRelationship,
+        ): dev.usbharu.hideout.core.application.relationship.Relationship {
+            return Relationship(
+                relationship.actorId.id,
+                relationship.targetActorId.id,
+                relationship.following,
+                relationship2.following,
+                relationship.blocking,
+                relationship2.blocking,
+                relationship.muting,
+                relationship.followRequesting,
+                relationship2.followRequesting,
+                actorInstanceRelationship.isBlocking(),
+                actorInstanceRelationship.isMuting(),
+                actorInstanceRelationship.isDoNotSendPrivate()
+            )
+        }
+    }
+}
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/Unblock.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/Unblock.kt
new file mode 100644
index 00000000..db5d856d
--- /dev/null
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/Unblock.kt
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2024 usbharu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dev.usbharu.hideout.core.application.relationship
+
+data class Unblock(val targetActorId: Long)
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/UserBlockApplicationService.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/UserBlockApplicationService.kt
new file mode 100644
index 00000000..8103b9e4
--- /dev/null
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/UserBlockApplicationService.kt
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2024 usbharu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dev.usbharu.hideout.core.application.relationship
+
+import dev.usbharu.hideout.core.application.shared.AbstractApplicationService
+import dev.usbharu.hideout.core.application.shared.CommandExecutor
+import dev.usbharu.hideout.core.application.shared.Transaction
+import dev.usbharu.hideout.core.application.shared.UserDetailGettableCommandExecutor
+import dev.usbharu.hideout.core.domain.model.actor.ActorId
+import dev.usbharu.hideout.core.domain.model.actor.ActorRepository
+import dev.usbharu.hideout.core.domain.model.relationship.Relationship
+import dev.usbharu.hideout.core.domain.model.relationship.RelationshipRepository
+import dev.usbharu.hideout.core.domain.model.userdetails.UserDetailRepository
+import dev.usbharu.hideout.core.domain.service.relationship.RelationshipDomainService
+import org.slf4j.LoggerFactory
+import org.springframework.stereotype.Service
+
+@Service
+class UserBlockApplicationService(
+    private val relationshipRepository: RelationshipRepository,
+    transaction: Transaction,
+    private val actorRepository: ActorRepository,
+    private val userDetailRepository: UserDetailRepository,
+    private val relationshipDomainService: RelationshipDomainService,
+) :
+    AbstractApplicationService<Block, Unit>(transaction, logger) {
+    companion object {
+        private val logger = LoggerFactory.getLogger(UserBlockApplicationService::class.java)
+    }
+
+    override suspend fun internalExecute(command: Block, executor: CommandExecutor) {
+        require(executor is UserDetailGettableCommandExecutor)
+
+        val userDetail = userDetailRepository.findById(executor.userDetailId)!!
+        val actor = actorRepository.findById(userDetail.actorId)!!
+
+        val targetId = ActorId(command.targetActorId)
+        val relationship = relationshipRepository.findByActorIdAndTargetId(actor.id, targetId) ?: Relationship.default(
+            actor.id,
+            targetId
+        )
+
+        val inverseRelationship =
+            relationshipRepository.findByActorIdAndTargetId(targetId, actor.id) ?: Relationship.default(
+                targetId,
+                actor.id
+            )
+
+        relationshipDomainService.block(relationship, inverseRelationship)
+
+
+        relationshipRepository.save(relationship)
+        relationshipRepository.save(inverseRelationship)
+    }
+}
\ No newline at end of file
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/UserFollowRequestApplicationService.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/UserFollowRequestApplicationService.kt
new file mode 100644
index 00000000..29c6f805
--- /dev/null
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/UserFollowRequestApplicationService.kt
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2024 usbharu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dev.usbharu.hideout.core.application.relationship
+
+import dev.usbharu.hideout.core.application.shared.AbstractApplicationService
+import dev.usbharu.hideout.core.application.shared.CommandExecutor
+import dev.usbharu.hideout.core.application.shared.Transaction
+import dev.usbharu.hideout.core.application.shared.UserDetailGettableCommandExecutor
+import dev.usbharu.hideout.core.domain.model.actor.ActorId
+import dev.usbharu.hideout.core.domain.model.actor.ActorRepository
+import dev.usbharu.hideout.core.domain.model.relationship.Relationship
+import dev.usbharu.hideout.core.domain.model.relationship.RelationshipRepository
+import dev.usbharu.hideout.core.domain.model.userdetails.UserDetailRepository
+import org.slf4j.LoggerFactory
+import org.springframework.stereotype.Service
+
+@Service
+class UserFollowRequestApplicationService(
+    private val relationshipRepository: RelationshipRepository,
+    transaction: Transaction,
+    private val actorRepository: ActorRepository,
+    private val userDetailRepository: UserDetailRepository,
+) : AbstractApplicationService<FollowRequest, Unit>(
+    transaction, logger
+) {
+
+    override suspend fun internalExecute(command: FollowRequest, executor: CommandExecutor) {
+        require(executor is UserDetailGettableCommandExecutor)
+
+        val userDetail = userDetailRepository.findById(executor.userDetailId)!!
+        val actor = actorRepository.findById(userDetail.actorId)!!
+
+        val targetId = ActorId(command.targetActorId)
+        val relationship = relationshipRepository.findByActorIdAndTargetId(actor.id, targetId) ?: Relationship.default(
+            actor.id,
+            targetId
+        )
+
+        relationship.followRequest()
+
+        relationshipRepository.save(relationship)
+    }
+
+    companion object {
+        private val logger = LoggerFactory.getLogger(UserFollowRequestApplicationService::class.java)
+    }
+}
\ No newline at end of file
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/UserUnblockApplicationService.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/UserUnblockApplicationService.kt
new file mode 100644
index 00000000..3bf42d3e
--- /dev/null
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/application/relationship/UserUnblockApplicationService.kt
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2024 usbharu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dev.usbharu.hideout.core.application.relationship
+
+import dev.usbharu.hideout.core.application.shared.AbstractApplicationService
+import dev.usbharu.hideout.core.application.shared.CommandExecutor
+import dev.usbharu.hideout.core.application.shared.Transaction
+import dev.usbharu.hideout.core.application.shared.UserDetailGettableCommandExecutor
+import dev.usbharu.hideout.core.domain.model.actor.ActorId
+import dev.usbharu.hideout.core.domain.model.actor.ActorRepository
+import dev.usbharu.hideout.core.domain.model.relationship.Relationship
+import dev.usbharu.hideout.core.domain.model.relationship.RelationshipRepository
+import dev.usbharu.hideout.core.domain.model.userdetails.UserDetailRepository
+import org.slf4j.LoggerFactory
+import org.springframework.stereotype.Service
+
+@Service
+class UserUnblockApplicationService(
+    private val relationshipRepository: RelationshipRepository,
+    transaction: Transaction,
+    private val actorRepository: ActorRepository,
+    private val userDetailRepository: UserDetailRepository,
+) :
+    AbstractApplicationService<Unblock, Unit>(transaction, logger) {
+    companion object {
+        private val logger = LoggerFactory.getLogger(UserBlockApplicationService::class.java)
+    }
+
+    override suspend fun internalExecute(command: Unblock, executor: CommandExecutor) {
+        require(executor is UserDetailGettableCommandExecutor)
+
+        val userDetail = userDetailRepository.findById(executor.userDetailId)!!
+        val actor = actorRepository.findById(userDetail.actorId)!!
+
+        val targetId = ActorId(command.targetActorId)
+        val relationship = relationshipRepository.findByActorIdAndTargetId(actor.id, targetId) ?: Relationship.default(
+            actor.id,
+            targetId
+        )
+
+        relationship.unblock()
+
+        relationshipRepository.save(relationship)
+    }
+}
\ No newline at end of file
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/actorinstancerelationship/ActorInstanceRelationship.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/actorinstancerelationship/ActorInstanceRelationship.kt
index 178716a0..3cef6c86 100644
--- a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/actorinstancerelationship/ActorInstanceRelationship.kt
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/actorinstancerelationship/ActorInstanceRelationship.kt
@@ -96,5 +96,15 @@ data class ActorInstanceRelationship(
                 ")"
     }
 
-
+    companion object {
+        fun default(actorId: ActorId, instanceId: InstanceId): ActorInstanceRelationship {
+            return ActorInstanceRelationship(
+                actorId = actorId,
+                instanceId = instanceId,
+                blocking = false,
+                muting = false,
+                doNotSendPrivate = false
+            )
+        }
+    }
 }
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/actorinstancerelationship/ActorInstanceRelationshipRepository.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/actorinstancerelationship/ActorInstanceRelationshipRepository.kt
index 5bc7abd5..ea2bba54 100644
--- a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/actorinstancerelationship/ActorInstanceRelationshipRepository.kt
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/actorinstancerelationship/ActorInstanceRelationshipRepository.kt
@@ -16,7 +16,11 @@
 
 package dev.usbharu.hideout.core.domain.model.actorinstancerelationship
 
+import dev.usbharu.hideout.core.domain.model.actor.ActorId
+import dev.usbharu.hideout.core.domain.model.instance.InstanceId
+
 interface ActorInstanceRelationshipRepository {
     suspend fun save(actorInstanceRelationship: ActorInstanceRelationship): ActorInstanceRelationship
     suspend fun delete(actorInstanceRelationship: ActorInstanceRelationship)
+    suspend fun findByActorIdAndInstanceId(actorId: ActorId, instanceId: InstanceId): ActorInstanceRelationship?
 }
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/relationship/Relationship.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/relationship/Relationship.kt
index dd06c900..930670a9 100644
--- a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/relationship/Relationship.kt
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/relationship/Relationship.kt
@@ -102,4 +102,35 @@ class Relationship(
     fun rejectFollowRequest() {
         followRequesting = false
     }
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (javaClass != other?.javaClass) return false
+
+        other as Relationship
+
+        if (actorId != other.actorId) return false
+        if (targetActorId != other.targetActorId) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var result = actorId.hashCode()
+        result = 31 * result + targetActorId.hashCode()
+        return result
+    }
+
+
+    companion object {
+        fun default(actorId: ActorId, targetActorId: ActorId): Relationship = Relationship(
+            actorId = actorId,
+            targetActorId = targetActorId,
+            following = false,
+            blocking = false,
+            muting = false,
+            followRequesting = false,
+            mutingFollowRequest = false
+        )
+    }
 }
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/relationship/RelationshipRepository.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/relationship/RelationshipRepository.kt
index 6b84b91c..d74884af 100644
--- a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/relationship/RelationshipRepository.kt
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/model/relationship/RelationshipRepository.kt
@@ -16,7 +16,10 @@
 
 package dev.usbharu.hideout.core.domain.model.relationship
 
+import dev.usbharu.hideout.core.domain.model.actor.ActorId
+
 interface RelationshipRepository {
     suspend fun save(relationship: Relationship): Relationship
     suspend fun delete(relationship: Relationship)
+    suspend fun findByActorIdAndTargetId(actorId: ActorId, targetId: ActorId): Relationship?
 }
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/service/relationship/RelationshipDomainService.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/service/relationship/RelationshipDomainService.kt
new file mode 100644
index 00000000..2c81724c
--- /dev/null
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/service/relationship/RelationshipDomainService.kt
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2024 usbharu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dev.usbharu.hideout.core.domain.service.relationship
+
+import dev.usbharu.hideout.core.domain.model.relationship.Relationship
+import org.springframework.stereotype.Service
+
+@Service
+class RelationshipDomainService {
+    fun block(relationship: Relationship, inverseRelationship: Relationship) {
+        require(relationship != inverseRelationship)
+        require(relationship.actorId == inverseRelationship.targetActorId)
+        require(relationship.targetActorId == inverseRelationship.actorId)
+
+        relationship.block()
+        inverseRelationship.unfollow()
+        inverseRelationship.unfollowRequest()
+    }
+}
\ No newline at end of file
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/infrastructure/exposedrepository/ExposedActorInstanceRelationshipRepository.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/infrastructure/exposedrepository/ExposedActorInstanceRelationshipRepository.kt
new file mode 100644
index 00000000..9cc1cfd4
--- /dev/null
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/infrastructure/exposedrepository/ExposedActorInstanceRelationshipRepository.kt
@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2024 usbharu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dev.usbharu.hideout.core.infrastructure.exposedrepository
+
+import dev.usbharu.hideout.core.domain.model.actor.ActorId
+import dev.usbharu.hideout.core.domain.model.actorinstancerelationship.ActorInstanceRelationship
+import dev.usbharu.hideout.core.domain.model.actorinstancerelationship.ActorInstanceRelationshipRepository
+import dev.usbharu.hideout.core.domain.model.instance.InstanceId
+import dev.usbharu.hideout.core.domain.shared.domainevent.DomainEventPublisher
+import dev.usbharu.hideout.core.domain.shared.repository.DomainEventPublishableRepository
+import org.jetbrains.exposed.sql.*
+import org.jetbrains.exposed.sql.SqlExpressionBuilder.eq
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
+import org.springframework.stereotype.Repository
+
+
+@Repository
+class ExposedActorInstanceRelationshipRepository(override val domainEventPublisher: DomainEventPublisher) :
+    ActorInstanceRelationshipRepository, AbstractRepository(),
+    DomainEventPublishableRepository<ActorInstanceRelationship> {
+    override suspend fun save(actorInstanceRelationship: ActorInstanceRelationship): ActorInstanceRelationship {
+        query {
+            ActorInstanceRelationships.upsert {
+                it[actorId] = actorInstanceRelationship.actorId.id
+                it[instanceId] = actorInstanceRelationship.instanceId.instanceId
+                it[blocking] = actorInstanceRelationship.isBlocking()
+                it[muting] = actorInstanceRelationship.isMuting()
+                it[doNotSendPrivate] = actorInstanceRelationship.isDoNotSendPrivate()
+            }
+        }
+        update(actorInstanceRelationship)
+        return actorInstanceRelationship
+    }
+
+    override suspend fun delete(actorInstanceRelationship: ActorInstanceRelationship) {
+        query {
+            ActorInstanceRelationships.deleteWhere {
+                actorId eq actorInstanceRelationship.actorId.id and (instanceId eq actorInstanceRelationship.instanceId.instanceId)
+            }
+        }
+        update(actorInstanceRelationship)
+    }
+
+    override suspend fun findByActorIdAndInstanceId(
+        actorId: ActorId,
+        instanceId: InstanceId,
+    ): ActorInstanceRelationship? = query {
+        ActorInstanceRelationships
+            .selectAll()
+            .where {
+                ActorInstanceRelationships.actorId eq actorId.id and (ActorInstanceRelationships.instanceId eq instanceId.instanceId)
+            }
+            .singleOrNull()
+            ?.toActorInstanceRelationship()
+    }
+
+    override val logger: Logger
+        get() = Companion.logger
+
+    companion object {
+        private val logger = LoggerFactory.getLogger(ExposedActorInstanceRelationshipRepository::class.java)
+    }
+}
+
+private fun ResultRow.toActorInstanceRelationship(): ActorInstanceRelationship {
+    return ActorInstanceRelationship(
+        actorId = ActorId(this[ActorInstanceRelationships.actorId]),
+        instanceId = InstanceId(this[ActorInstanceRelationships.instanceId]),
+        blocking = this[ActorInstanceRelationships.blocking],
+        muting = this[ActorInstanceRelationships.muting],
+        doNotSendPrivate = this[ActorInstanceRelationships.doNotSendPrivate],
+    )
+}
+
+object ActorInstanceRelationships : Table("actor_instance_relationships") {
+    val actorId = long("actor_id").references(Actors.id)
+    val instanceId = long("instance_id").references(Instance.id)
+    val blocking = bool("blocking")
+    val muting = bool("muting")
+    val doNotSendPrivate = bool("do_not_send_private")
+
+    override val primaryKey: PrimaryKey = PrimaryKey(actorId, instanceId)
+}
\ No newline at end of file
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/infrastructure/exposedrepository/ExposedRelationshipRepository.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/infrastructure/exposedrepository/ExposedRelationshipRepository.kt
new file mode 100644
index 00000000..eef233b0
--- /dev/null
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/infrastructure/exposedrepository/ExposedRelationshipRepository.kt
@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2024 usbharu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dev.usbharu.hideout.core.infrastructure.exposedrepository
+
+import dev.usbharu.hideout.core.domain.model.actor.ActorId
+import dev.usbharu.hideout.core.domain.model.relationship.Relationship
+import dev.usbharu.hideout.core.domain.model.relationship.RelationshipRepository
+import dev.usbharu.hideout.core.domain.shared.domainevent.DomainEventPublisher
+import dev.usbharu.hideout.core.domain.shared.repository.DomainEventPublishableRepository
+import org.jetbrains.exposed.sql.*
+import org.jetbrains.exposed.sql.SqlExpressionBuilder.eq
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
+import org.springframework.stereotype.Repository
+
+@Repository
+class ExposedRelationshipRepository(override val domainEventPublisher: DomainEventPublisher) : RelationshipRepository,
+    AbstractRepository(),
+    DomainEventPublishableRepository<Relationship> {
+    override suspend fun save(relationship: Relationship): Relationship {
+        query {
+            Relationships.upsert {
+                it[actorId] = relationship.actorId.id
+                it[targetActorId] = relationship.targetActorId.id
+                it[following] = relationship.following
+                it[blocking] = relationship.blocking
+                it[muting] = relationship.muting
+                it[followRequesting] = relationship.followRequesting
+                it[mutingFollowRequest] = relationship.mutingFollowRequest
+            }
+        }
+        update(relationship)
+        return relationship
+    }
+
+    override suspend fun delete(relationship: Relationship) {
+        query {
+            Relationships.deleteWhere {
+                actorId eq relationship.actorId.id and (targetActorId eq relationship.targetActorId.id)
+            }
+        }
+        update(relationship)
+    }
+
+    override suspend fun findByActorIdAndTargetId(actorId: ActorId, targetId: ActorId): Relationship? = query {
+        Relationships.selectAll().where {
+            Relationships.actorId eq actorId.id and (Relationships.targetActorId eq targetId.id)
+        }.singleOrNull()?.toRelationships()
+    }
+
+    override val logger: Logger
+        get() = Companion.logger
+
+
+    companion object {
+        private val logger = LoggerFactory.getLogger(ExposedRelationshipRepository::class.java)
+    }
+}
+
+fun ResultRow.toRelationships(): Relationship = Relationship(
+    actorId = ActorId(this[Relationships.actorId]),
+    targetActorId = ActorId(this[Relationships.targetActorId]),
+    following = this[Relationships.following],
+    blocking = this[Relationships.blocking],
+    muting = this[Relationships.muting],
+    followRequesting = this[Relationships.followRequesting],
+    mutingFollowRequest = this[Relationships.mutingFollowRequest]
+)
+
+object Relationships : Table("relationships") {
+    val actorId = long("actor_id").references(Actors.id)
+    val targetActorId = long("target_actor_id").references(Actors.id)
+    val following = bool("following")
+    val blocking = bool("blocking")
+    val muting = bool("muting")
+    val followRequesting = bool("follow_requesting")
+    val mutingFollowRequest = bool("muting_follow_request")
+
+    override val primaryKey: PrimaryKey = PrimaryKey(actorId, targetActorId)
+}
\ No newline at end of file
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/infrastructure/springframework/oauth2/Oauth2CommandExecutor.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/infrastructure/springframework/oauth2/Oauth2CommandExecutor.kt
index 23f8a73e..3dd05d31 100644
--- a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/infrastructure/springframework/oauth2/Oauth2CommandExecutor.kt
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/infrastructure/springframework/oauth2/Oauth2CommandExecutor.kt
@@ -17,5 +17,7 @@
 package dev.usbharu.hideout.core.infrastructure.springframework.oauth2
 
 import dev.usbharu.hideout.core.application.shared.CommandExecutor
+import dev.usbharu.hideout.core.application.shared.UserDetailGettableCommandExecutor
 
-class Oauth2CommandExecutor(override val executor: String, val userDetailId: Long) : CommandExecutor
\ No newline at end of file
+class Oauth2CommandExecutor(override val executor: String, override val userDetailId: Long) : CommandExecutor,
+    UserDetailGettableCommandExecutor
\ No newline at end of file
diff --git a/hideout-core/src/main/resources/db/migration/V1__Init_DB.sql b/hideout-core/src/main/resources/db/migration/V1__Init_DB.sql
index dc757618..fdc8afea 100644
--- a/hideout-core/src/main/resources/db/migration/V1__Init_DB.sql
+++ b/hideout-core/src/main/resources/db/migration/V1__Init_DB.sql
@@ -249,3 +249,15 @@ CREATE TABLE oauth2_authorization
     device_code_metadata          varchar(4000) DEFAULT NULL,
     PRIMARY KEY (id)
 );
+
+create table if not exists actor_instance_relationships
+(
+    actor_id            bigint  not null,
+    instance_id         bigint  not null,
+    blocking            boolean not null,
+    muting              boolean not null,
+    do_not_send_private boolean not null,
+    PRIMARY KEY (actor_id, instance_id),
+    constraint fk_actor_instance_relationships_actor_id__id foreign key (actor_id) references actors (id) on delete cascade on update cascade,
+    constraint fk_actor_instance_relationships_instance_id__id foreign key (instance_id) references instance (id) on delete cascade on update cascade
+);
\ No newline at end of file
diff --git a/hideout-mastodon/src/main/kotlin/dev/usbharu/hideout/mastodon/application/accounts/GetAccount.kt b/hideout-mastodon/src/main/kotlin/dev/usbharu/hideout/mastodon/application/accounts/GetAccount.kt
new file mode 100644
index 00000000..340607b9
--- /dev/null
+++ b/hideout-mastodon/src/main/kotlin/dev/usbharu/hideout/mastodon/application/accounts/GetAccount.kt
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2024 usbharu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dev.usbharu.hideout.mastodon.application.accounts
+
+data class GetAccount(val accountId: String)
diff --git a/hideout-mastodon/src/main/kotlin/dev/usbharu/hideout/mastodon/application/accounts/GetAccountApplicationService.kt b/hideout-mastodon/src/main/kotlin/dev/usbharu/hideout/mastodon/application/accounts/GetAccountApplicationService.kt
new file mode 100644
index 00000000..5fb7249f
--- /dev/null
+++ b/hideout-mastodon/src/main/kotlin/dev/usbharu/hideout/mastodon/application/accounts/GetAccountApplicationService.kt
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2024 usbharu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dev.usbharu.hideout.mastodon.application.accounts
+
+import dev.usbharu.hideout.core.application.shared.AbstractApplicationService
+import dev.usbharu.hideout.core.application.shared.CommandExecutor
+import dev.usbharu.hideout.core.application.shared.Transaction
+import dev.usbharu.hideout.mastodon.interfaces.api.generated.model.Account
+import dev.usbharu.hideout.mastodon.query.AccountQueryService
+import org.slf4j.LoggerFactory
+import org.springframework.stereotype.Service
+
+@Service
+class GetAccountApplicationService(private val accountQueryService: AccountQueryService, transaction: Transaction) :
+    AbstractApplicationService<GetAccount, Account>(
+        transaction,
+        logger
+    ) {
+    override suspend fun internalExecute(command: GetAccount, executor: CommandExecutor): Account {
+        return accountQueryService.findById(command.accountId.toLong()) ?: throw Exception("Account not found")
+    }
+
+    companion object {
+        private val logger = LoggerFactory.getLogger(GetAccountApplicationService::class.java)
+    }
+}
\ No newline at end of file
diff --git a/hideout-mastodon/src/main/kotlin/dev/usbharu/hideout/mastodon/interfaces/api/SpringAccountApi.kt b/hideout-mastodon/src/main/kotlin/dev/usbharu/hideout/mastodon/interfaces/api/SpringAccountApi.kt
index 7483eda8..8367597f 100644
--- a/hideout-mastodon/src/main/kotlin/dev/usbharu/hideout/mastodon/interfaces/api/SpringAccountApi.kt
+++ b/hideout-mastodon/src/main/kotlin/dev/usbharu/hideout/mastodon/interfaces/api/SpringAccountApi.kt
@@ -18,9 +18,14 @@ package dev.usbharu.hideout.mastodon.interfaces.api
 
 import dev.usbharu.hideout.core.application.actor.GetUserDetail
 import dev.usbharu.hideout.core.application.actor.GetUserDetailApplicationService
+import dev.usbharu.hideout.core.application.relationship.*
+import dev.usbharu.hideout.core.infrastructure.springframework.oauth2.Oauth2CommandExecutor
 import dev.usbharu.hideout.core.infrastructure.springframework.oauth2.Oauth2CommandExecutorFactory
+import dev.usbharu.hideout.mastodon.application.accounts.GetAccount
+import dev.usbharu.hideout.mastodon.application.accounts.GetAccountApplicationService
 import dev.usbharu.hideout.mastodon.interfaces.api.generated.AccountApi
 import dev.usbharu.hideout.mastodon.interfaces.api.generated.model.*
+import dev.usbharu.hideout.mastodon.interfaces.api.generated.model.Relationship
 import org.springframework.http.ResponseEntity
 import org.springframework.stereotype.Controller
 
@@ -28,20 +33,60 @@ import org.springframework.stereotype.Controller
 class SpringAccountApi(
     private val oauth2CommandExecutorFactory: Oauth2CommandExecutorFactory,
     private val getUserDetailApplicationService: GetUserDetailApplicationService,
+    private val getAccountApplicationService: GetAccountApplicationService,
+    private val userFollowRequestApplicationService: UserFollowRequestApplicationService,
+    private val getRelationshipApplicationService: GetRelationshipApplicationService,
+    private val userBlockApplicationService: UserBlockApplicationService,
+    private val userUnblockApplicationService: UserUnblockApplicationService,
 ) : AccountApi {
     override suspend fun apiV1AccountsIdBlockPost(id: String): ResponseEntity<Relationship> {
-        return super.apiV1AccountsIdBlockPost(id)
+        val executor = oauth2CommandExecutorFactory.getCommandExecutor()
+        userBlockApplicationService.execute(Block(id.toLong()), executor)
+        return fetchRelationship(id, executor)
     }
 
     override suspend fun apiV1AccountsIdFollowPost(
         id: String,
         followRequestBody: FollowRequestBody?,
     ): ResponseEntity<Relationship> {
-        return super.apiV1AccountsIdFollowPost(id, followRequestBody)
+        val executor = oauth2CommandExecutorFactory.getCommandExecutor()
+        userFollowRequestApplicationService.execute(
+            FollowRequest(id.toLong()), executor
+        )
+        return fetchRelationship(id, executor)
+    }
+
+    private suspend fun fetchRelationship(
+        id: String,
+        executor: Oauth2CommandExecutor,
+    ): ResponseEntity<Relationship> {
+        val relationship = getRelationshipApplicationService.execute(GetRelationship(id.toLong()), executor)
+        return ResponseEntity.ok(
+            Relationship(
+                id = relationship.targetId.toString(),
+                following = relationship.following,
+                showingReblogs = true,
+                notifying = false,
+                followedBy = relationship.followedBy,
+                blocking = relationship.blocking,
+                blockedBy = relationship.blockedBy,
+                muting = relationship.muting,
+                mutingNotifications = false,
+                requested = relationship.followRequesting,
+                domainBlocking = relationship.domainBlocking,
+                endorsed = false,
+                note = ""
+            )
+        )
     }
 
     override suspend fun apiV1AccountsIdGet(id: String): ResponseEntity<Account> {
-        return super.apiV1AccountsIdGet(id)
+        return ResponseEntity.ok(
+            getAccountApplicationService.execute(
+                GetAccount(id),
+                oauth2CommandExecutorFactory.getCommandExecutor()
+            )
+        )
     }
 
     override suspend fun apiV1AccountsIdMutePost(id: String): ResponseEntity<Relationship> {
@@ -53,7 +98,11 @@ class SpringAccountApi(
     }
 
     override suspend fun apiV1AccountsIdUnblockPost(id: String): ResponseEntity<Relationship> {
-        return super.apiV1AccountsIdUnblockPost(id)
+        val executor = oauth2CommandExecutorFactory.getCommandExecutor()
+        userUnblockApplicationService.execute(
+            Unblock(id.toLong()), executor
+        )
+        return fetchRelationship(id, executor)
     }
 
     override suspend fun apiV1AccountsIdUnfollowPost(id: String): ResponseEntity<Relationship> {