diff --git a/packages/backend/src/core/ProxyAccountService.ts b/packages/backend/src/core/ProxyAccountService.ts
index c3ff2a68d3..f776d72405 100644
--- a/packages/backend/src/core/ProxyAccountService.ts
+++ b/packages/backend/src/core/ProxyAccountService.ts
@@ -4,25 +4,54 @@
  */
 
 import { Inject, Injectable } from '@nestjs/common';
+import { IsNull } from 'typeorm';
 import type { MiMeta, UsersRepository } from '@/models/_.js';
 import type { MiLocalUser } from '@/models/User.js';
 import { DI } from '@/di-symbols.js';
 import { bindThis } from '@/decorators.js';
+import { CreateSystemUserService } from '@/core/CreateSystemUserService.js';
+import { MemorySingleCache } from '@/misc/cache.js';
+import { MetaService } from '@/core/MetaService.js';
+
+const ACTOR_USERNAME = 'proxy.actor' as const;
 
 @Injectable()
 export class ProxyAccountService {
+	private cache: MemorySingleCache<MiLocalUser>;
+
 	constructor(
 		@Inject(DI.meta)
 		private meta: MiMeta,
 
 		@Inject(DI.usersRepository)
 		private usersRepository: UsersRepository,
+
+		private createSystemUserService: CreateSystemUserService,
+		private metaService: MetaService,
 	) {
+		this.cache = new MemorySingleCache<MiLocalUser>(Infinity);
 	}
 
 	@bindThis
 	public async fetch(): Promise<MiLocalUser | null> {
-		if (this.meta.proxyAccountId == null) return null;
-		return await this.usersRepository.findOneByOrFail({ id: this.meta.proxyAccountId }) as MiLocalUser;
+		const cached = this.cache.get();
+		if (cached) return cached;
+
+		const user = await this.usersRepository.findOneBy({
+			host: IsNull(),
+			username: ACTOR_USERNAME,
+		}) as MiLocalUser | undefined;
+
+		if (user) {
+			this.cache.set(user);
+			return user;
+		} else {
+			const created = await this.createSystemUserService.createSystemUser(ACTOR_USERNAME) as MiLocalUser;
+			this.cache.set(created);
+			const set = {} as Partial<MiMeta>;
+			set.proxyAccountId = created.id;
+			await this.metaService.update(set);
+			return created;
+		}
 	}
 }