diff --git a/blocks/flag.ts b/blocks/flag.ts
index f4937d5b..ca480c74 100644
--- a/blocks/flag.ts
+++ b/blocks/flag.ts
@@ -5,6 +5,7 @@ import JsonViewer from "../components/JsonViewer.tsx";
 import type { Block, BlockModule, InstanceOf } from "../engine/block.ts";
 import { isDeferred } from "../engine/core/resolver.ts";
 import { type Device, deviceOf } from "../utils/userAgent.ts";
+
 export type Flag = InstanceOf<typeof flagBlock, "#/root/flags">;
 
 export interface FlagObj<TVariant = unknown> {
@@ -64,7 +65,7 @@ const flagBlock: Block<BlockModule<FlagFunc>> = {
   >(func: {
     default: FlagFunc<TConfig>;
   }) =>
-  ($live: TConfig, { request }: HttpContext) => {
+  async ($live: TConfig, { request }: HttpContext) => {
     const flag = func.default($live);
     let device: Device | null = null;
     const ctx = {
@@ -75,12 +76,16 @@ const flagBlock: Block<BlockModule<FlagFunc>> = {
       },
     };
     if (isMultivariate(flag)) {
-      const value = ((flag?.variants ?? []).find((variant) =>
-        typeof variant?.rule === "function" && variant?.rule(ctx)
-      ) as Variant<unknown>)?.value ??
-        ((flag?.variants ?? [])[flag?.variants?.length - 1] as Variant<unknown>)
-          ?.value;
-      return isDeferred(value) ? value() : value;
+      const variants = flag.variants || [];
+
+      const results = await Promise.all(
+        variants.map((variant) =>
+          typeof variant?.rule === "function" ? variant.rule(ctx) : false
+        ),
+      );
+      const match = variants.find((_, index) => results[index]) || variants[0];
+
+      return isDeferred(match?.value) ? match?.value() : match?.value;
     }
     const matchValue = typeof flag?.matcher === "function"
       ? flag.matcher(ctx)