diff --git a/app/src/main/java/kr/co/vividnext/sodalive/v2/creator/channel/community/detail/reply/CreatorChannelCommunityReplyViewModel.kt b/app/src/main/java/kr/co/vividnext/sodalive/v2/creator/channel/community/detail/reply/CreatorChannelCommunityReplyViewModel.kt
new file mode 100644
index 00000000..7093841e
--- /dev/null
+++ b/app/src/main/java/kr/co/vividnext/sodalive/v2/creator/channel/community/detail/reply/CreatorChannelCommunityReplyViewModel.kt
@@ -0,0 +1,373 @@
+package kr.co.vividnext.sodalive.v2.creator.channel.community.detail.reply
+
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MutableLiveData
+import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers
+import io.reactivex.rxjava3.schedulers.Schedulers
+import kr.co.vividnext.sodalive.R
+import kr.co.vividnext.sodalive.audio_content.comment.ModifyCommentRequest
+import kr.co.vividnext.sodalive.base.BaseViewModel
+import kr.co.vividnext.sodalive.common.ApiResponse
+import kr.co.vividnext.sodalive.common.SharedPreferenceManager
+import kr.co.vividnext.sodalive.common.ToastMessage
+import kr.co.vividnext.sodalive.common.UtcRelativeTimeTextFormatter
+import kr.co.vividnext.sodalive.explorer.profile.creator_community.CreatorCommunityRepository
+import kr.co.vividnext.sodalive.v2.creator.channel.CreatorChannelEvent
+import kr.co.vividnext.sodalive.v2.creator.channel.community.detail.CreatorChannelCommunityCommentUiModel
+import kr.co.vividnext.sodalive.v2.creator.channel.community.detail.CreatorChannelCommunityReplyUiModel
+import kr.co.vividnext.sodalive.v2.creator.channel.community.detail.data.CreatorChannelCommunityRepliesResponse
+import kr.co.vividnext.sodalive.v2.creator.channel.community.detail.data.CreatorChannelCommunityReplyResponse
+import kr.co.vividnext.sodalive.v2.creator.channel.data.CreatorChannelRepository
+
+class CreatorChannelCommunityReplyViewModel(
+    private val repository: CreatorChannelRepository,
+    private val legacyRepository: CreatorCommunityRepository,
+    private val relativeTimeTextFormatter: UtcRelativeTimeTextFormatter
+) : BaseViewModel() {
+
+    private val _replyStateLiveData = MutableLiveData<CreatorChannelCommunityReplyUiState>()
+    val replyStateLiveData: LiveData<CreatorChannelCommunityReplyUiState>
+        get() = _replyStateLiveData
+
+    private val _replyWrittenEventLiveData = MutableLiveData<Boolean>()
+    val replyWrittenEventLiveData: LiveData<Boolean>
+        get() = _replyWrittenEventLiveData
+
+    private val _replyChangedEventLiveData = MutableLiveData<Boolean>()
+    val replyChangedEventLiveData: LiveData<Boolean>
+        get() = _replyChangedEventLiveData
+
+    private val _parentCommentChangedEventLiveData = MutableLiveData<Boolean>()
+    val parentCommentChangedEventLiveData: LiveData<Boolean>
+        get() = _parentCommentChangedEventLiveData
+
+    private val _parentCommentDeletedEventLiveData = MutableLiveData<Boolean>()
+    val parentCommentDeletedEventLiveData: LiveData<Boolean>
+        get() = _parentCommentDeletedEventLiveData
+
+    private val _toastLiveData = MutableLiveData<CreatorChannelEvent<ToastMessage>>()
+    val toastLiveData: LiveData<CreatorChannelEvent<ToastMessage>>
+        get() = _toastLiveData
+
+    private var postId: Long = 0L
+    private var parentComment: CreatorChannelCommunityCommentUiModel? = null
+    private var replyRequestGeneration = 0
+    private var isLoadingReplies = false
+    private var isSendingReply = false
+    private var isModifyingReply = false
+
+    fun loadReplies(postId: Long, parentComment: CreatorChannelCommunityCommentUiModel) {
+        val formattedParentComment = parentComment.copy(
+            createdAtText = relativeTimeTextFormatter.format(parentComment.createdAtUtc)
+        )
+        this.postId = postId
+        this.parentComment = formattedParentComment
+        replyRequestGeneration++
+        isLoadingReplies = false
+        _replyStateLiveData.value = CreatorChannelCommunityReplyUiState.Content(
+            parentComment = formattedParentComment,
+            replies = emptyList(),
+            replyPage = FIRST_PAGE,
+            hasNextReply = false
+        )
+        if (formattedParentComment.commentId > 0) {
+            loadReplyPage(page = FIRST_PAGE, append = false)
+        }
+    }
+
+    fun loadMoreReplies() {
+        val content = _replyStateLiveData.value as? CreatorChannelCommunityReplyUiState.Content ?: return
+        if (!content.hasNextReply || isLoadingReplies) return
+
+        loadReplyPage(page = content.replyPage + 1, append = true)
+    }
+
+    fun updateReplyInput(input: String) {
+        val content = _replyStateLiveData.value as? CreatorChannelCommunityReplyUiState.Content ?: return
+        _replyStateLiveData.value = content.copy(replyInput = input)
+    }
+
+    fun submitReply() {
+        val content = _replyStateLiveData.value as? CreatorChannelCommunityReplyUiState.Content ?: return
+        val comment = content.replyInput.trim()
+        val commentId = content.parentComment.commentId
+        if (postId <= 0 || commentId <= 0 || comment.isBlank() || isSendingReply) return
+
+        isSendingReply = true
+        _replyStateLiveData.value = content.copy(isSendingReply = true)
+        compositeDisposable.add(
+            legacyRepository.registerComment(
+                postId = postId,
+                comment = comment,
+                parentId = commentId,
+                isSecret = false,
+                token = authToken()
+            )
+                .subscribeOn(Schedulers.io())
+                .observeOn(AndroidSchedulers.mainThread())
+                .subscribe(
+                    { response -> handleWriteResponse(response) },
+                    {
+                        isSendingReply = false
+                        val current = _replyStateLiveData.value as? CreatorChannelCommunityReplyUiState.Content
+                            ?: return@subscribe
+                        showMutationFailureToast()
+                        _replyStateLiveData.value = current.copy(isSendingReply = false)
+                    }
+                )
+        )
+    }
+
+    fun consumeReplyWrittenEvent() {
+        _replyWrittenEventLiveData.value = false
+    }
+
+    fun consumeReplyChangedEvent() {
+        _replyChangedEventLiveData.value = false
+    }
+
+    fun consumeParentCommentChangedEvent() {
+        _parentCommentChangedEventLiveData.value = false
+    }
+
+    fun consumeParentCommentDeletedEvent() {
+        _parentCommentDeletedEventLiveData.value = false
+    }
+
+    fun modifyReply(replyId: Long, comment: String) {
+        val trimmedComment = comment.trim()
+        if (replyId <= 0 || isModifyingReply) return
+        if (trimmedComment.isBlank()) {
+            showBlankCommentToast()
+            return
+        }
+
+        modifyComment(ModifyCommentRequest(commentId = replyId, comment = trimmedComment))
+    }
+
+    fun deleteReply(replyId: Long) {
+        if (replyId <= 0 || isModifyingReply) return
+
+        modifyComment(ModifyCommentRequest(commentId = replyId, isActive = false))
+    }
+
+    fun modifyParentComment(comment: String) {
+        val parentComment = parentComment ?: return
+        val trimmedComment = comment.trim()
+        if (parentComment.commentId <= 0 || isModifyingReply) return
+        if (trimmedComment.isBlank()) {
+            showBlankCommentToast()
+            return
+        }
+
+        modifyParentComment(parentComment, trimmedComment)
+    }
+
+    fun deleteParentComment() {
+        val parentComment = parentComment ?: return
+        if (parentComment.commentId <= 0 || isModifyingReply) return
+
+        deleteParentComment(parentComment.commentId)
+    }
+
+    private fun modifyParentComment(parentComment: CreatorChannelCommunityCommentUiModel, comment: String) {
+        isModifyingReply = true
+        compositeDisposable.add(
+            legacyRepository.modifyComment(
+                ModifyCommentRequest(commentId = parentComment.commentId, comment = comment),
+                authToken()
+            )
+                .subscribeOn(Schedulers.io())
+                .observeOn(AndroidSchedulers.mainThread())
+                .subscribe(
+                    { response ->
+                        isModifyingReply = false
+                        if (response.success) {
+                            val updatedParent = parentComment.copy(comment = comment)
+                            this.parentComment = updatedParent
+                            val current = _replyStateLiveData.value as? CreatorChannelCommunityReplyUiState.Content
+                                ?: return@subscribe
+                            _replyStateLiveData.value = current.copy(parentComment = updatedParent)
+                            _parentCommentChangedEventLiveData.value = true
+                        } else {
+                            showMutationFailureToast(response.message)
+                        }
+                    },
+                    {
+                        isModifyingReply = false
+                        showMutationFailureToast()
+                    }
+                )
+        )
+    }
+
+    private fun deleteParentComment(commentId: Long) {
+        isModifyingReply = true
+        compositeDisposable.add(
+            legacyRepository.modifyComment(ModifyCommentRequest(commentId = commentId, isActive = false), authToken())
+                .subscribeOn(Schedulers.io())
+                .observeOn(AndroidSchedulers.mainThread())
+                .subscribe(
+                    { response ->
+                        isModifyingReply = false
+                        if (response.success) {
+                            _parentCommentDeletedEventLiveData.value = true
+                        } else {
+                            showMutationFailureToast(response.message)
+                        }
+                    },
+                    {
+                        isModifyingReply = false
+                        showMutationFailureToast()
+                    }
+                )
+        )
+    }
+
+    private fun loadReplyPage(page: Int, append: Boolean) {
+        val commentId = parentComment?.commentId ?: return
+        if (commentId <= 0 || isLoadingReplies && append) return
+        val generation = if (append) {
+            replyRequestGeneration
+        } else {
+            ++replyRequestGeneration
+        }
+
+        isLoadingReplies = true
+        val beforeRequest = _replyStateLiveData.value as? CreatorChannelCommunityReplyUiState.Content
+        if (beforeRequest != null) {
+            _replyStateLiveData.value = beforeRequest.copy(isLoadingReplies = true)
+        }
+        compositeDisposable.add(
+            repository.getCommunityCommentReplies(commentId, page, DEFAULT_PAGE_SIZE, authToken())
+                .subscribeOn(Schedulers.io())
+                .observeOn(AndroidSchedulers.mainThread())
+                .subscribe(
+                    { response -> handleRepliesResponse(response, append, generation) },
+                    {
+                        if (generation != replyRequestGeneration) return@subscribe
+
+                        isLoadingReplies = false
+                        val current = _replyStateLiveData.value as? CreatorChannelCommunityReplyUiState.Content
+                            ?: return@subscribe
+                        _replyStateLiveData.value = current.copy(isLoadingReplies = false)
+                    }
+                )
+        )
+    }
+
+    private fun handleRepliesResponse(
+        response: ApiResponse<CreatorChannelCommunityRepliesResponse>,
+        append: Boolean,
+        generation: Int
+    ) {
+        if (generation != replyRequestGeneration) return
+
+        isLoadingReplies = false
+        val current = _replyStateLiveData.value as? CreatorChannelCommunityReplyUiState.Content ?: return
+        val data = response.data
+        if (!response.success || data == null) {
+            _replyStateLiveData.value = current.copy(isLoadingReplies = false)
+            return
+        }
+
+        val nextReplies = data.replies.map { it.toUiModel() }
+        _replyStateLiveData.value = current.copy(
+            replies = if (append) current.replies + nextReplies else nextReplies,
+            replyPage = data.page,
+            hasNextReply = data.hasNext,
+            isLoadingReplies = false
+        )
+    }
+
+    private fun handleWriteResponse(response: ApiResponse<Any>) {
+        isSendingReply = false
+        val current = _replyStateLiveData.value as? CreatorChannelCommunityReplyUiState.Content ?: return
+        if (response.success) {
+            _replyWrittenEventLiveData.value = true
+            _replyChangedEventLiveData.value = true
+            _replyStateLiveData.value = current.copy(replyInput = "", isSendingReply = false)
+            loadReplyPage(page = FIRST_PAGE, append = false)
+        } else {
+            showMutationFailureToast(response.message)
+            _replyStateLiveData.value = current.copy(isSendingReply = false)
+        }
+    }
+
+    private fun modifyComment(request: ModifyCommentRequest) {
+        val commentId = parentComment?.commentId ?: return
+        if (commentId <= 0) return
+
+        isModifyingReply = true
+        compositeDisposable.add(
+            legacyRepository.modifyComment(request, authToken())
+                .subscribeOn(Schedulers.io())
+                .observeOn(AndroidSchedulers.mainThread())
+                .subscribe(
+                    { response ->
+                        isModifyingReply = false
+                        if (response.success) {
+                            _replyChangedEventLiveData.value = true
+                            loadReplyPage(page = FIRST_PAGE, append = false)
+                        } else {
+                            showMutationFailureToast(response.message)
+                        }
+                    },
+                    {
+                        isModifyingReply = false
+                        showMutationFailureToast()
+                    }
+                )
+        )
+    }
+
+    private fun showMutationFailureToast(message: String? = null) {
+        _toastLiveData.value = CreatorChannelEvent(
+            if (message.isNullOrBlank()) {
+                ToastMessage(resId = R.string.common_error_unknown)
+            } else {
+                ToastMessage(message = message)
+            }
+        )
+    }
+
+    private fun showBlankCommentToast() {
+        _toastLiveData.value = CreatorChannelEvent(
+            ToastMessage(resId = R.string.screen_creator_community_write_content_hint)
+        )
+    }
+
+    private fun CreatorChannelCommunityReplyResponse.toUiModel() = CreatorChannelCommunityReplyUiModel(
+        replyId = commentId,
+        commentId = parentComment?.commentId ?: 0L,
+        memberId = writerId,
+        memberNickname = writerNickname,
+        memberProfileUrl = writerProfileImageUrl,
+        createdAtUtc = createdAtUtc,
+        createdAtText = relativeTimeTextFormatter.format(createdAtUtc),
+        comment = content,
+        likeCount = 0,
+        isLiked = false,
+        isMine = writerId == SharedPreferenceManager.userId,
+        isCreatorOwner = parentComment?.isCreatorOwner == true
+    )
+
+    private fun authToken(): String = "Bearer ${SharedPreferenceManager.token}"
+
+    companion object {
+        const val DEFAULT_PAGE_SIZE = 20
+        private const val FIRST_PAGE = 0
+    }
+}
+
+sealed interface CreatorChannelCommunityReplyUiState {
+    data class Content(
+        val parentComment: CreatorChannelCommunityCommentUiModel,
+        val replies: List<CreatorChannelCommunityReplyUiModel>,
+        val replyPage: Int,
+        val hasNextReply: Boolean,
+        val isLoadingReplies: Boolean = false,
+        val replyInput: String = "",
+        val isSendingReply: Boolean = false
+    ) : CreatorChannelCommunityReplyUiState
+}
diff --git a/app/src/test/java/kr/co/vividnext/sodalive/v2/creator/channel/community/CreatorChannelCommunityReplyViewModelTest.kt b/app/src/test/java/kr/co/vividnext/sodalive/v2/creator/channel/community/CreatorChannelCommunityReplyViewModelTest.kt
new file mode 100644
index 00000000..eea36f46
--- /dev/null
+++ b/app/src/test/java/kr/co/vividnext/sodalive/v2/creator/channel/community/CreatorChannelCommunityReplyViewModelTest.kt
@@ -0,0 +1,446 @@
+package kr.co.vividnext.sodalive.v2.creator.channel.community
+
+import android.app.Application
+import android.content.Context
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.Observer
+import androidx.test.core.app.ApplicationProvider
+import io.reactivex.rxjava3.android.plugins.RxAndroidPlugins
+import io.reactivex.rxjava3.core.Scheduler
+import io.reactivex.rxjava3.core.Single
+import io.reactivex.rxjava3.plugins.RxJavaPlugins
+import io.reactivex.rxjava3.schedulers.Schedulers
+import io.reactivex.rxjava3.subjects.PublishSubject
+import kr.co.vividnext.sodalive.audio_content.comment.ModifyCommentRequest
+import kr.co.vividnext.sodalive.common.ApiResponse
+import kr.co.vividnext.sodalive.common.SharedPreferenceManager
+import kr.co.vividnext.sodalive.common.UtcRelativeTimeTextFormatter
+import kr.co.vividnext.sodalive.explorer.profile.creator_community.CreatorCommunityRepository
+import kr.co.vividnext.sodalive.v2.creator.channel.community.detail.CreatorChannelCommunityCommentUiModel
+import kr.co.vividnext.sodalive.v2.creator.channel.community.detail.reply.CreatorChannelCommunityReplyUiState
+import kr.co.vividnext.sodalive.v2.creator.channel.community.detail.reply.CreatorChannelCommunityReplyViewModel
+import kr.co.vividnext.sodalive.v2.creator.channel.community.detail.data.CreatorChannelCommunityRepliesResponse
+import kr.co.vividnext.sodalive.v2.creator.channel.community.detail.data.CreatorChannelCommunityReplyResponse
+import kr.co.vividnext.sodalive.v2.creator.channel.data.CreatorChannelRepository
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.kotlin.any
+import org.mockito.kotlin.argThat
+import org.mockito.kotlin.never
+import org.mockito.kotlin.times
+import org.mockito.kotlin.verify
+import org.mockito.kotlin.whenever
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [28], application = Application::class)
+class CreatorChannelCommunityReplyViewModelTest {
+
+    private val context: Context = ApplicationProvider.getApplicationContext()
+    private lateinit var repository: CreatorChannelRepository
+    private lateinit var legacyRepository: CreatorCommunityRepository
+    private lateinit var viewModel: CreatorChannelCommunityReplyViewModel
+    private lateinit var formattedInputs: MutableList<String?>
+
+    @Before
+    fun setUp() {
+        setImmediateRxSchedulers()
+        SharedPreferenceManager.resetForTest()
+        SharedPreferenceManager.init(context)
+        SharedPreferenceManager.token = "test-token"
+        SharedPreferenceManager.userId = 10L
+        repository = org.mockito.kotlin.mock()
+        legacyRepository = org.mockito.kotlin.mock()
+        formattedInputs = mutableListOf()
+        viewModel = CreatorChannelCommunityReplyViewModel(
+            repository,
+            legacyRepository,
+            UtcRelativeTimeTextFormatter { value ->
+                formattedInputs.add(value)
+                "relative:$value"
+            }
+        )
+    }
+
+    @After
+    fun tearDown() {
+        RxJavaPlugins.reset()
+        RxAndroidPlugins.reset()
+        SharedPreferenceManager.resetForTest()
+    }
+
+    @Test
+    fun `답글 로드는 부모 댓글을 노출하고 첫 페이지 답글을 매핑한다`() {
+        stubReplies(repliesResponse(ids = listOf(101L, 102L), hasNext = true))
+
+        viewModel.loadReplies(POST_ID, parentComment())
+
+        val state = viewModel.replyStateLiveData.requireValue() as CreatorChannelCommunityReplyUiState.Content
+        assertEquals(COMMENT_ID, state.parentComment.commentId)
+        assertEquals("부모 댓글", state.parentComment.comment)
+        assertEquals("relative:2026-07-08T00:00:00Z", state.parentComment.createdAtText)
+        assertEquals(listOf(101L, 102L), state.replies.map { it.replyId })
+        assertTrue(formattedInputs.contains("2026-07-08T00:00:00Z"))
+        assertEquals(0, state.replyPage)
+        assertTrue(state.hasNextReply)
+        verify(repository).getCommunityCommentReplies(
+            COMMENT_ID,
+            0,
+            CreatorChannelCommunityReplyViewModel.DEFAULT_PAGE_SIZE,
+            AUTH_TOKEN
+        )
+    }
+
+    @Test
+    fun `답글 페이지네이션은 hasNext일 때 다음 페이지를 append하고 중복 loadMore를 막는다`() {
+        whenever(
+            repository.getCommunityCommentReplies(
+                COMMENT_ID,
+                0,
+                CreatorChannelCommunityReplyViewModel.DEFAULT_PAGE_SIZE,
+                AUTH_TOKEN
+            )
+        )
+            .thenReturn(Single.just(ApiResponse(true, repliesResponse(ids = listOf(101L), hasNext = true), null)))
+        whenever(
+            repository.getCommunityCommentReplies(
+                COMMENT_ID,
+                1,
+                CreatorChannelCommunityReplyViewModel.DEFAULT_PAGE_SIZE,
+                AUTH_TOKEN
+            )
+        )
+            .thenReturn(Single.just(ApiResponse(true, repliesResponse(page = 1, ids = listOf(102L), hasNext = false), null)))
+        viewModel.loadReplies(POST_ID, parentComment())
+
+        viewModel.loadMoreReplies()
+        viewModel.loadMoreReplies()
+
+        val state = viewModel.replyStateLiveData.requireValue() as CreatorChannelCommunityReplyUiState.Content
+        assertEquals(listOf(101L, 102L), state.replies.map { it.replyId })
+        assertEquals(1, state.replyPage)
+        assertFalse(state.hasNextReply)
+        verify(repository, times(1)).getCommunityCommentReplies(
+            COMMENT_ID,
+            1,
+            CreatorChannelCommunityReplyViewModel.DEFAULT_PAGE_SIZE,
+            AUTH_TOKEN
+        )
+    }
+
+    @Test
+    fun `답글 작성은 trim 후 전송하고 중복 전송을 막고 성공 시 입력과 이벤트를 정리하며 새로고침한다`() {
+        whenever(
+            repository.getCommunityCommentReplies(
+                COMMENT_ID,
+                0,
+                CreatorChannelCommunityReplyViewModel.DEFAULT_PAGE_SIZE,
+                AUTH_TOKEN
+            )
+        )
+            .thenReturn(
+                Single.just(ApiResponse(true, repliesResponse(ids = listOf(101L), hasNext = false), null)),
+                Single.just(ApiResponse(true, repliesResponse(ids = listOf(201L), hasNext = false), null))
+            )
+        val sendSubject = PublishSubject.create<ApiResponse<Any>>()
+        whenever(legacyRepository.registerComment(POST_ID, "hello", COMMENT_ID, false, AUTH_TOKEN))
+            .thenReturn(sendSubject.firstOrError())
+        viewModel.loadReplies(POST_ID, parentComment())
+
+        viewModel.updateReplyInput("   ")
+        viewModel.submitReply()
+        viewModel.updateReplyInput("  hello  ")
+        viewModel.submitReply()
+        viewModel.submitReply()
+
+        verify(legacyRepository, times(1)).registerComment(POST_ID, "hello", COMMENT_ID, false, AUTH_TOKEN)
+
+        sendSubject.onNext(ApiResponse(true, Any(), null))
+
+        val state = viewModel.replyStateLiveData.requireValue() as CreatorChannelCommunityReplyUiState.Content
+        assertEquals("", state.replyInput)
+        assertTrue(viewModel.replyWrittenEventLiveData.requireValue() == true)
+        assertTrue(viewModel.replyChangedEventLiveData.requireValue() == true)
+        viewModel.consumeReplyChangedEvent()
+        assertFalse(viewModel.replyChangedEventLiveData.requireValue() == true)
+        viewModel.consumeReplyWrittenEvent()
+        assertFalse(viewModel.replyWrittenEventLiveData.requireValue() == true)
+        assertEquals(listOf(201L), state.replies.map { it.replyId })
+        verify(repository, times(2)).getCommunityCommentReplies(
+            COMMENT_ID,
+            0,
+            CreatorChannelCommunityReplyViewModel.DEFAULT_PAGE_SIZE,
+            AUTH_TOKEN
+        )
+    }
+
+    @Test
+    fun `답글 작성 실패는 API 메시지 toast 이벤트를 노출하고 입력 상태를 유지한다`() {
+        stubReplies(repliesResponse(ids = listOf(101L), hasNext = false))
+        whenever(legacyRepository.registerComment(POST_ID, "hello", COMMENT_ID, false, AUTH_TOKEN))
+            .thenReturn(Single.just(ApiResponse(false, Any(), "답글 실패")))
+        viewModel.loadReplies(POST_ID, parentComment())
+
+        viewModel.updateReplyInput("hello")
+        viewModel.submitReply()
+
+        val state = viewModel.replyStateLiveData.requireValue() as CreatorChannelCommunityReplyUiState.Content
+        assertEquals("hello", state.replyInput)
+        assertFalse(state.isSendingReply)
+        assertEquals("답글 실패", viewModel.toastLiveData.requireValue()?.consume()?.message)
+        assertEquals(null, viewModel.toastLiveData.requireValue()?.consume())
+    }
+
+    @Test
+    fun `답글 삭제 실패는 알 수 없는 오류 toast 이벤트를 노출한다`() {
+        stubReplies(repliesResponse(ids = listOf(101L), hasNext = false))
+        whenever(legacyRepository.modifyComment(any(), org.mockito.kotlin.eq(AUTH_TOKEN)))
+            .thenReturn(Single.error(RuntimeException("network")))
+        viewModel.loadReplies(POST_ID, parentComment())
+
+        viewModel.deleteReply(REPLY_ID)
+
+        assertEquals(
+            kr.co.vividnext.sodalive.R.string.common_error_unknown,
+            viewModel.toastLiveData.requireValue()?.consume()?.resId
+        )
+    }
+
+    @Test
+    fun `답글 수정 내용이 공백이면 내용 입력 toast를 노출하고 API를 호출하지 않는다`() {
+        stubReplies(repliesResponse(ids = listOf(101L), hasNext = false))
+        viewModel.loadReplies(POST_ID, parentComment())
+
+        viewModel.modifyReply(REPLY_ID, "   ")
+
+        assertEquals(
+            kr.co.vividnext.sodalive.R.string.screen_creator_community_write_content_hint,
+            viewModel.toastLiveData.requireValue()?.consume()?.resId
+        )
+        verify(legacyRepository, never()).modifyComment(any(), any())
+    }
+
+    @Test
+    fun `답글 수정과 삭제는 legacy modifyComment를 호출하고 성공 시 답글을 새로고침한다`() {
+        whenever(
+            repository.getCommunityCommentReplies(
+                COMMENT_ID,
+                0,
+                CreatorChannelCommunityReplyViewModel.DEFAULT_PAGE_SIZE,
+                AUTH_TOKEN
+            )
+        )
+            .thenReturn(
+                Single.just(ApiResponse(true, repliesResponse(ids = listOf(101L), hasNext = false), null)),
+                Single.just(ApiResponse(true, repliesResponse(ids = listOf(102L), hasNext = false), null)),
+                Single.just(ApiResponse(true, repliesResponse(ids = listOf(103L), hasNext = false), null))
+            )
+        whenever(legacyRepository.modifyComment(any(), org.mockito.kotlin.eq(AUTH_TOKEN)))
+            .thenReturn(Single.just(ApiResponse(true, Any(), null)))
+        viewModel.loadReplies(POST_ID, parentComment())
+
+        viewModel.modifyReply(REPLY_ID, "  수정 댓글  ")
+        viewModel.deleteReply(REPLY_ID)
+
+        verify(legacyRepository).modifyComment(
+            argThat<ModifyCommentRequest> { commentId == REPLY_ID && comment == "수정 댓글" && isActive == null },
+            org.mockito.kotlin.eq(AUTH_TOKEN)
+        )
+        verify(legacyRepository).modifyComment(
+            argThat<ModifyCommentRequest> { commentId == REPLY_ID && comment == null && isActive == false },
+            org.mockito.kotlin.eq(AUTH_TOKEN)
+        )
+        verify(repository, times(3)).getCommunityCommentReplies(
+            COMMENT_ID,
+            0,
+            CreatorChannelCommunityReplyViewModel.DEFAULT_PAGE_SIZE,
+            AUTH_TOKEN
+        )
+        assertTrue(viewModel.replyChangedEventLiveData.requireValue() == true)
+    }
+
+    @Test
+    fun `부모 댓글 수정은 legacy modifyComment를 호출하고 성공 시 부모 댓글 상태와 변경 이벤트를 갱신한다`() {
+        stubReplies(repliesResponse(ids = listOf(101L), hasNext = false))
+        whenever(legacyRepository.modifyComment(any(), org.mockito.kotlin.eq(AUTH_TOKEN)))
+            .thenReturn(Single.just(ApiResponse(true, Any(), null)))
+        viewModel.loadReplies(POST_ID, parentComment())
+
+        viewModel.modifyParentComment("  수정 부모 댓글  ")
+
+        val state = viewModel.replyStateLiveData.requireValue() as CreatorChannelCommunityReplyUiState.Content
+        assertEquals("수정 부모 댓글", state.parentComment.comment)
+        assertTrue(viewModel.parentCommentChangedEventLiveData.requireValue() == true)
+        viewModel.consumeParentCommentChangedEvent()
+        assertFalse(viewModel.parentCommentChangedEventLiveData.requireValue() == true)
+
+        verify(legacyRepository).modifyComment(
+            argThat<ModifyCommentRequest> { commentId == COMMENT_ID && comment == "수정 부모 댓글" && isActive == null },
+            org.mockito.kotlin.eq(AUTH_TOKEN)
+        )
+        verify(repository, times(1)).getCommunityCommentReplies(
+            COMMENT_ID,
+            0,
+            CreatorChannelCommunityReplyViewModel.DEFAULT_PAGE_SIZE,
+            AUTH_TOKEN
+        )
+    }
+
+    @Test
+    fun `부모 댓글 수정 내용이 공백이면 내용 입력 toast를 노출하고 API를 호출하지 않는다`() {
+        stubReplies(repliesResponse(ids = listOf(101L), hasNext = false))
+        viewModel.loadReplies(POST_ID, parentComment())
+
+        viewModel.modifyParentComment("   ")
+
+        assertEquals(
+            kr.co.vividnext.sodalive.R.string.screen_creator_community_write_content_hint,
+            viewModel.toastLiveData.requireValue()?.consume()?.resId
+        )
+        verify(legacyRepository, never()).modifyComment(any(), any())
+    }
+
+    @Test
+    fun `부모 댓글 삭제는 legacy modifyComment를 호출하고 성공 시 삭제 이벤트만 노출한다`() {
+        stubReplies(repliesResponse(ids = listOf(101L), hasNext = false))
+        whenever(legacyRepository.modifyComment(any(), org.mockito.kotlin.eq(AUTH_TOKEN)))
+            .thenReturn(Single.just(ApiResponse(true, Any(), null)))
+        viewModel.loadReplies(POST_ID, parentComment())
+
+        viewModel.deleteParentComment()
+
+        assertTrue(viewModel.parentCommentDeletedEventLiveData.requireValue() == true)
+        viewModel.consumeParentCommentDeletedEvent()
+        assertFalse(viewModel.parentCommentDeletedEventLiveData.requireValue() == true)
+        verify(legacyRepository).modifyComment(
+            argThat<ModifyCommentRequest> { commentId == COMMENT_ID && comment == null && isActive == false },
+            org.mockito.kotlin.eq(AUTH_TOKEN)
+        )
+        verify(repository, times(1)).getCommunityCommentReplies(
+            COMMENT_ID,
+            0,
+            CreatorChannelCommunityReplyViewModel.DEFAULT_PAGE_SIZE,
+            AUTH_TOKEN
+        )
+    }
+
+    @Test
+    fun `댓글 id가 유효하지 않으면 답글 API를 호출하지 않는다`() {
+        viewModel.loadReplies(POST_ID, parentComment(commentId = 0L))
+
+        val state = viewModel.replyStateLiveData.requireValue() as CreatorChannelCommunityReplyUiState.Content
+        assertTrue(state.replies.isEmpty())
+        verify(repository, never()).getCommunityCommentReplies(any(), any(), any(), any())
+    }
+
+    @Test
+    fun `새 답글 로드 후 이전 답글 페이지 응답이 도착해도 현재 답글 목록을 덮지 않는다`() {
+        val loadMoreSubject = PublishSubject.create<ApiResponse<CreatorChannelCommunityRepliesResponse>>()
+        whenever(
+            repository.getCommunityCommentReplies(
+                COMMENT_ID,
+                0,
+                CreatorChannelCommunityReplyViewModel.DEFAULT_PAGE_SIZE,
+                AUTH_TOKEN
+            )
+        )
+            .thenReturn(
+                Single.just(ApiResponse(true, repliesResponse(ids = listOf(101L), hasNext = true), null)),
+                Single.just(ApiResponse(true, repliesResponse(ids = listOf(201L), hasNext = false), null))
+            )
+        whenever(
+            repository.getCommunityCommentReplies(
+                COMMENT_ID,
+                1,
+                CreatorChannelCommunityReplyViewModel.DEFAULT_PAGE_SIZE,
+                AUTH_TOKEN
+            )
+        ).thenReturn(loadMoreSubject.firstOrError())
+
+        viewModel.loadReplies(POST_ID, parentComment())
+        viewModel.loadMoreReplies()
+        viewModel.loadReplies(POST_ID, parentComment())
+        loadMoreSubject.onNext(ApiResponse(true, repliesResponse(page = 1, ids = listOf(999L), hasNext = false), null))
+
+        val state = viewModel.replyStateLiveData.requireValue() as CreatorChannelCommunityReplyUiState.Content
+        assertEquals(listOf(201L), state.replies.map { it.replyId })
+        assertEquals(0, state.replyPage)
+        assertFalse(state.hasNextReply)
+    }
+
+    private fun stubReplies(response: CreatorChannelCommunityRepliesResponse) {
+        whenever(
+            repository.getCommunityCommentReplies(
+                COMMENT_ID,
+                0,
+                CreatorChannelCommunityReplyViewModel.DEFAULT_PAGE_SIZE,
+                AUTH_TOKEN
+            )
+        )
+            .thenReturn(Single.just(ApiResponse(true, response, null)))
+    }
+
+    private fun repliesResponse(
+        page: Int = 0,
+        ids: List<Long>,
+        hasNext: Boolean
+    ) = CreatorChannelCommunityRepliesResponse(
+        replies = ids.map { replyResponse(it) },
+        page = page,
+        size = CreatorChannelCommunityReplyViewModel.DEFAULT_PAGE_SIZE,
+        hasNext = hasNext
+    )
+
+    private fun replyResponse(id: Long) = CreatorChannelCommunityReplyResponse(
+        commentId = id,
+        writerId = 10L,
+        writerProfileImageUrl = "member.png",
+        writerNickname = "member $id",
+        content = "reply $id",
+        createdAtUtc = "2026-07-08T00:00:00Z"
+    )
+
+    private fun parentComment(commentId: Long = COMMENT_ID) = CreatorChannelCommunityCommentUiModel(
+        commentId = commentId,
+        memberId = 10L,
+        memberNickname = "member",
+        memberProfileUrl = "member.png",
+        createdAtText = "이미 포맷된 시간",
+        createdAtUtc = "2026-07-08T00:00:00Z",
+        comment = "부모 댓글",
+        likeCount = 1,
+        replyCount = 2,
+        isLiked = false,
+        isMine = true,
+        isCreatorOwner = false,
+        latestReply = null
+    )
+
+    private fun setImmediateRxSchedulers() {
+        val trampoline = { _: Scheduler -> Schedulers.trampoline() }
+        RxJavaPlugins.setIoSchedulerHandler(trampoline)
+        RxAndroidPlugins.setInitMainThreadSchedulerHandler { Schedulers.trampoline() }
+        RxAndroidPlugins.setMainThreadSchedulerHandler { Schedulers.trampoline() }
+    }
+
+    private fun <T> LiveData<T>.requireValue(): T? {
+        var value: T? = null
+        val observer = Observer<T> { value = it }
+        observeForever(observer)
+        removeObserver(observer)
+        return value
+    }
+
+    private companion object {
+        const val POST_ID = 200L
+        const val COMMENT_ID = 300L
+        const val REPLY_ID = 101L
+        const val AUTH_TOKEN = "Bearer test-token"
+    }
+}