diff --git a/packages/backend/src/db/scylla.ts b/packages/backend/src/db/scylla.ts
index 2b6dd800ef..eacb7fc95f 100644
--- a/packages/backend/src/db/scylla.ts
+++ b/packages/backend/src/db/scylla.ts
@@ -1,6 +1,7 @@
 import config from "@/config/index.js";
-import { DriveFile } from "@/models/entities/drive-file.js";
-import { Client } from "cassandra-driver";
+import type { PopulatedEmoji } from "@/misc/populate-emojis.js";
+import type { NoteReaction } from "@/models/entities/note-reaction.js";
+import { Client, types } from "cassandra-driver";
 
 function newClient(): Client | null {
 	if (!config.scylla) {
@@ -52,11 +53,11 @@ export const prepared = {
 			VALUES
 			(?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
 		select: {
-			byDate: `SELECT * FROM note WHERE "createdAtDate" = ? AND "createdAt" < ?`,
+			byDate: `SELECT * FROM note WHERE "createdAtDate" IN ?`,
 			byId: `SELECT * FROM note WHERE "id" IN ?`,
-			byUri: `SELECT * FROM note WHERE "uri" = ?`,
-			byUrl: `SELECT * FROM note WHERE "url" = ?`,
-			byUserId: `SELECT * FROM note_by_userid WHERE "userId" = ? AND "createdAt" < ?`,
+			byUri: `SELECT * FROM note WHERE "uri" IN ?`,
+			byUrl: `SELECT * FROM note WHERE "url" IN ?`,
+			byUserId: `SELECT * FROM note_by_userid WHERE "userId" IN ?`,
 		},
 		delete: `DELETE FROM note WHERE "createdAtDate" = ? AND "createdAt" = ?`,
 		update: {
@@ -68,6 +69,13 @@ export const prepared = {
 		insert: `INSERT INTO reaction
 			("id", "noteId", "userId", "reaction", "emoji", "createdAt")
 			VALUES (?, ?, ?, ?, ?, ?)`,
+		select: {
+			byNoteId: `SELECT * FROM reaction WHERE "noteId" IN ?`,
+			byUserId: `SELECT * FROM reaction_by_userid WHERE "userId" IN ?`,
+			byNoteAndUser: `SELECT * FROM reaction WHERE "noteId" = ? AND "userId" = ?`,
+			byId: `SELECT * FROM reaction WHERE "id" IN ?`,
+		},
+		delete: `DELETE FROM reaction WHERE "noteId" = ? AND "userId" = ?`,
 	},
 };
 
@@ -87,3 +95,18 @@ export interface ScyllaDriveFile {
 	width: number;
 	height: number;
 }
+
+export type ScyllaNoteReaction = NoteReaction & {
+	emoji: PopulatedEmoji
+}
+
+export function parseScyllaReaction(row: types.Row): ScyllaNoteReaction {
+	return {
+		id: row.get("id"),
+		noteId: row.get("noteId"),
+		userId: row.get("userId"),
+		reaction: row.get("reaction"),
+		createdAt: row.get("createdAt"),
+		emoji: row.get("emoji"),
+	}
+}
diff --git a/packages/backend/src/misc/populate-emojis.ts b/packages/backend/src/misc/populate-emojis.ts
index b53e065892..c9ba9e323d 100644
--- a/packages/backend/src/misc/populate-emojis.ts
+++ b/packages/backend/src/misc/populate-emojis.ts
@@ -14,7 +14,7 @@ export const EmojiCache = new Cache<Emoji | null>("populateEmojis", 60 * 60 * 12
 /**
  * 添付用絵文字情報
  */
-type PopulatedEmoji = {
+export type PopulatedEmoji = {
 	name: string;
 	url: string;
 	width: number | null;
diff --git a/packages/backend/src/services/note/create.ts b/packages/backend/src/services/note/create.ts
index ce5827642a..e396b0b232 100644
--- a/packages/backend/src/services/note/create.ts
+++ b/packages/backend/src/services/note/create.ts
@@ -67,10 +67,8 @@ import { shouldSilenceInstance } from "@/misc/should-block-instance.js";
 import meilisearch from "../../db/meilisearch.js";
 import { redisClient } from "@/db/redis.js";
 import { Mutex } from "redis-semaphore";
-import { prepared, scyllaClient, ScyllaDriveFile } from "@/db/scylla.js";
+import { prepared, scyllaClient } from "@/db/scylla.js";
 import { populateEmojis } from "@/misc/populate-emojis.js";
-import { decodeReaction } from "@/misc/reaction-lib.js";
-import { types } from "cassandra-driver";
 
 const mutedWordsCache = new Cache<
 	{ userId: UserProfile["userId"]; mutedWords: UserProfile["mutedWords"] }[]
diff --git a/packages/backend/src/services/note/delete.ts b/packages/backend/src/services/note/delete.ts
index 90175ccdc4..b810744bee 100644
--- a/packages/backend/src/services/note/delete.ts
+++ b/packages/backend/src/services/note/delete.ts
@@ -22,6 +22,7 @@ import { countSameRenotes } from "@/misc/count-same-renotes.js";
 import { registerOrFetchInstanceDoc } from "../register-or-fetch-instance-doc.js";
 import { deliverToRelays } from "../relay.js";
 import meilisearch from "@/db/meilisearch.js";
+import { prepared, scyllaClient } from "@/db/scylla.js";
 
 /**
  * 投稿を削除します。
@@ -116,6 +117,13 @@ export default async function (
 		}
 	}
 
+	if (scyllaClient) {
+		const date = new Date(note.createdAt.getTime());
+		await scyllaClient.execute(prepared.note.delete, [date, date], {
+			prepare: true,
+		});
+	}
+
 	await Notes.delete({
 		id: note.id,
 		userId: user.id,
diff --git a/packages/backend/src/services/note/reaction/create.ts b/packages/backend/src/services/note/reaction/create.ts
index 038e904db5..893f239632 100644
--- a/packages/backend/src/services/note/reaction/create.ts
+++ b/packages/backend/src/services/note/reaction/create.ts
@@ -68,7 +68,14 @@ export default async (
 			// Thus, a reaction by the same user will be replaced if exists.
 			await scyllaClient.execute(
 				prepared.reaction.insert,
-				[record.id, record.noteId, record.userId, _reaction, emojiData, record.createdAt],
+				[
+					record.id,
+					record.noteId,
+					record.userId,
+					_reaction,
+					emojiData,
+					record.createdAt,
+				],
 				{ prepare: true },
 			);
 		} else {
diff --git a/packages/backend/src/services/note/reaction/delete.ts b/packages/backend/src/services/note/reaction/delete.ts
index 15c6d1cf62..c044596274 100644
--- a/packages/backend/src/services/note/reaction/delete.ts
+++ b/packages/backend/src/services/note/reaction/delete.ts
@@ -8,28 +8,39 @@ import type { User, IRemoteUser } from "@/models/entities/user.js";
 import type { Note } from "@/models/entities/note.js";
 import { NoteReactions, Users, Notes } from "@/models/index.js";
 import { decodeReaction } from "@/misc/reaction-lib.js";
+import { parseScyllaReaction, prepared, scyllaClient } from "@/db/scylla";
+import type { NoteReaction } from "@/models/entities/note-reaction.js";
 
 export default async (
 	user: { id: User["id"]; host: User["host"] },
 	note: Note,
 ) => {
-	const reaction = await NoteReactions.findOneBy({
-		noteId: note.id,
-		userId: user.id,
-	});
-
-	// if already unreacted
-	if (reaction == null) {
-		throw new IdentifiableError(
-			"60527ec9-b4cb-4a88-a6bd-32d3ad26817d",
-			"not reacted",
+	let reaction: NoteReaction | null;
+	if (scyllaClient) {
+		const result = await scyllaClient.execute(
+			prepared.reaction.select.byNoteAndUser,
+			[note.id, user.id],
+			{ prepare: true },
 		);
+		reaction =
+			result.rowLength > 0 ? parseScyllaReaction(result.rows[0]) : null;
+	} else {
+		reaction = await NoteReactions.findOneBy({
+			noteId: note.id,
+			userId: user.id,
+		});
 	}
 
 	// Delete reaction
-	const result = await NoteReactions.delete(reaction.id);
-
-	if (result.affected !== 1) {
+	if (reaction) {
+		if (scyllaClient) {
+			await scyllaClient.execute(prepared.reaction.delete, [note.id, user.id], {
+				prepare: true,
+			});
+		} else {
+			await NoteReactions.delete(reaction.id);
+		}
+	} else {
 		throw new IdentifiableError(
 			"60527ec9-b4cb-4a88-a6bd-32d3ad26817d",
 			"not reacted",
@@ -37,16 +48,31 @@ export default async (
 	}
 
 	// Decrement reactions count
-	const sql = `jsonb_set("reactions", '{${reaction.reaction}}', (COALESCE("reactions"->>'${reaction.reaction}', '0')::int - 1)::text::jsonb)`;
-	await Notes.createQueryBuilder()
-		.update()
-		.set({
-			reactions: () => sql,
-		})
-		.where("id = :id", { id: note.id })
-		.execute();
+	if (scyllaClient) {
+		const count = Math.max((note.reactions[reaction.reaction] ?? 0) - 1, 0);
+		if (count === 0) {
+			delete note.reactions[reaction.reaction];
+		} else {
+			note.reactions[reaction.reaction] = count;
+		}
+		const date = new Date(note.createdAt.getTime());
+		await scyllaClient.execute(
+			prepared.note.update.reactions,
+			[note.reactions, Math.max((note.score ?? 0) - 1, 0), date, date],
+			{ prepare: true },
+		);
+	} else {
+		const sql = `jsonb_set("reactions", '{${reaction.reaction}}', (COALESCE("reactions"->>'${reaction.reaction}', '0')::int - 1)::text::jsonb)`;
+		await Notes.createQueryBuilder()
+			.update()
+			.set({
+				reactions: () => sql,
+			})
+			.where("id = :id", { id: note.id })
+			.execute();
 
-	Notes.decrement({ id: note.id }, "score", 1);
+		Notes.decrement({ id: note.id }, "score", 1);
+	}
 
 	publishNoteStream(note.id, "unreacted", {
 		reaction: decodeReaction(reaction.reaction).reaction,