diff --git a/packages/frontend/assets/kawaii/LICENSE_MisskeyHQ b/packages/frontend/assets/kawaii/LICENSE_MisskeyHQ
new file mode 100644
index 000000000000..8b7ee5a2f657
--- /dev/null
+++ b/packages/frontend/assets/kawaii/LICENSE_MisskeyHQ
@@ -0,0 +1,20 @@
+LICENSE
+-------
+
+The following files:
+
+- misskey-io.png
+
+are owned by MisskeyHQ and are subject to copyright, with all rights reserved by MisskeyHQ. These files may not be redistributed, modified, or reused in any way without explicit permission from MisskeyHQ.
+
+Copyright (c) 2024 MisskeyHQ
+
+All rights reserved.
+
+This digital asset and related documentation are the property of MisskeyHQ.
+
+Permission is hereby granted to the user of this digital asset and related documentation to use, copy, and publish the asset for any purpose, provided that this notice and disclaimer of warranty appears in all copies. The user is expressly prohibited from distributing, sublicensing, selling, reselling, or transferring the asset for profit. Any form of modification or tampering with the asset is strictly prohibited.
+
+IN NO EVENT SHALL MISSKEYHQ BE LIABLE FOR ANY DAMAGES WHATSOEVER, INCLUDING BUT NOT LIMITED TO DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES, ARISING OUT OF THE USE, COPYING, PUBLISHING, OR MODIFICATION OF THIS ASSET.
+
+NO WARRANTIES OF ANY KIND ARE OFFERED FOR THIS ASSET. THIS ASSET IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED. USE AT YOUR OWN RISK.
diff --git a/packages/frontend/assets/kawaii/LICENSE_SAWARATSUKI b/packages/frontend/assets/kawaii/LICENSE_SAWARATSUKI
new file mode 100644
index 000000000000..0711c57dd83d
--- /dev/null
+++ b/packages/frontend/assets/kawaii/LICENSE_SAWARATSUKI
@@ -0,0 +1,12 @@
+LICENSE
+-------
+
+Copyright (c) by [さわらつき](https://github.com/SAWARATSUKI)
+
+The following files:
+
+- about-icon.png
+
+are licensed under a Creative Commons Attribution 4.0 International License.
+These files SHOULD NOT be considered as a part of the this project that has licensed under AGPL-3.0-only
+You should have received a copy of the license along with this work. If not, see <https://creativecommons.org/licenses/by/4.0/>.
diff --git a/packages/frontend/assets/kawaii/about-icon.png b/packages/frontend/assets/kawaii/about-icon.png
new file mode 100644
index 000000000000..e85cabba72cc
Binary files /dev/null and b/packages/frontend/assets/kawaii/about-icon.png differ
diff --git a/packages/frontend/assets/kawaii/misskey-io.png b/packages/frontend/assets/kawaii/misskey-io.png
new file mode 100644
index 000000000000..2fca378c819b
Binary files /dev/null and b/packages/frontend/assets/kawaii/misskey-io.png differ
diff --git a/packages/frontend/src/boot/common.ts b/packages/frontend/src/boot/common.ts
index d86ae18ffeac..c4f7a9a8dbfc 100644
--- a/packages/frontend/src/boot/common.ts
+++ b/packages/frontend/src/boot/common.ts
@@ -124,8 +124,8 @@ export async function common(createVue: () => App<Element>) {
 		miLocalStorage.setItem('v', instance.version);
 	});
 
-	//#region loginId
 	const params = new URLSearchParams(location.search);
+	//#region loginId
 	const loginId = params.get('loginId');
 
 	if (loginId) {
@@ -142,6 +142,14 @@ export async function common(createVue: () => App<Element>) {
 	}
 	//#endregion
 
+	//#region kawaii
+	if (params.has('kawaii')) {
+		miLocalStorage.setItem('kawaii', 'true');
+	} else {
+		miLocalStorage.removeItem('kawaii');
+	}
+	//#endregion
+
 	// NOTE: この処理は必ずクライアント更新チェック処理より後に来ること(テーマ再構築のため)
 	watch(defaultStore.reactiveState.darkMode, (darkMode) => {
 		applyTheme(darkMode ? ColdDeviceStorage.get('darkTheme') : ColdDeviceStorage.get('lightTheme'));
diff --git a/packages/frontend/src/components/MkVisitorDashboard.vue b/packages/frontend/src/components/MkVisitorDashboard.vue
index 54333cd4e9bf..6e653ea4cce1 100644
--- a/packages/frontend/src/components/MkVisitorDashboard.vue
+++ b/packages/frontend/src/components/MkVisitorDashboard.vue
@@ -6,7 +6,8 @@ SPDX-License-Identifier: AGPL-3.0-only
 <template>
 <div v-if="instance" :class="$style.root">
 	<div :class="[$style.main, $style.panel]">
-		<img :src="instance.iconUrl || '/favicon.ico'" alt="" :class="$style.mainIcon"/>
+		<img v-if="miLocalStorage.getItem('kawaii')" src="/client-assets/kawaii/misskey-io.png" alt="Logo by @sawaratsuki@misskey.io" :class="$style.mainIconAlt"/>
+		<img v-else :src="instance.iconUrl || '/favicon.ico'" alt="" :class="$style.mainIcon"/>
 		<button class="_button _acrylic" :class="$style.mainMenu" @click="showMenu"><i class="ti ti-dots"></i></button>
 		<div :class="$style.mainFg">
 			<h1 :class="$style.mainTitle">
@@ -81,6 +82,7 @@ import * as os from '@/os.js';
 import { misskeyApi } from '@/scripts/misskey-api.js';
 import { i18n } from '@/i18n.js';
 import { instance } from '@/instance.js';
+import { miLocalStorage } from '@/local-storage.js';
 import MkNumber from '@/components/MkNumber.vue';
 import XActiveUsersChart from '@/components/MkVisitorDashboard.ActiveUsersChart.vue';
 import { openInstanceMenu } from '@/ui/_common_/common';
@@ -139,6 +141,13 @@ function exploreOtherServers() {
 	filter: drop-shadow(0 2px 5px rgba(0, 0, 0, 0.5));
 }
 
+.mainIconAlt {
+	width: 85%;
+	margin-top: -47px;
+	vertical-align: bottom;
+	filter: drop-shadow(0 2px 5px rgba(0, 0, 0, 0.5));
+}
+
 .mainMenu {
 	position: absolute;
 	top: 16px;
diff --git a/packages/frontend/src/local-storage.ts b/packages/frontend/src/local-storage.ts
index 8029bca68d53..1cf543886ea0 100644
--- a/packages/frontend/src/local-storage.ts
+++ b/packages/frontend/src/local-storage.ts
@@ -38,7 +38,8 @@ type Keys =
 	`aiscript:${string}` |
 	'lastEmojisFetchedAt' | // DEPRECATED, stored in indexeddb (13.9.0~)
 	'emojis' | // DEPRECATED, stored in indexeddb (13.9.0~);
-	`channelLastReadedAt:${string}`
+	`channelLastReadedAt:${string}` |
+	'kawaii'
 
 export const miLocalStorage = {
 	getItem: (key: Keys): string | null => window.localStorage.getItem(key),
diff --git a/packages/frontend/src/pages/about-misskey.vue b/packages/frontend/src/pages/about-misskey.vue
index 3d33c44473ec..595f98f8127e 100644
--- a/packages/frontend/src/pages/about-misskey.vue
+++ b/packages/frontend/src/pages/about-misskey.vue
@@ -11,7 +11,9 @@ SPDX-License-Identifier: AGPL-3.0-only
 			<div class="_gaps_m znqjceqz">
 				<div v-panel class="about">
 					<div ref="containerEl" class="container" :class="{ playing: easterEggEngine != null }">
-						<img src="/client-assets/about-icon.png" alt="" class="icon" draggable="false" @load="iconLoaded" @click="gravity"/>
+						<img v-if="miLocalStorage.getItem('kawaii')" src="/client-assets/kawaii/about-icon.png" alt="" class="iconAlt" draggable="false" @load="iconLoaded" @click="gravity"/>
+						<img v-else src="/client-assets/about-icon.png" alt="" class="icon" draggable="false" @load="iconLoaded" @click="gravity"/>
+						<Mfm v-if="miLocalStorage.getItem('kawaii')" text="Logo by @sawaratsuki@misskey.io" class="iconCredit"/>
 						<div class="misskey">Misskey</div>
 						<div class="version">v{{ version }}</div>
 						<span v-for="emoji in easterEggEmojis" :key="emoji.id" class="emoji" :data-physics-x="emoji.left" :data-physics-y="emoji.top" :class="{ _physics_circle_: !emoji.emoji.startsWith(':') }">
@@ -137,6 +139,7 @@ import { physics } from '@/scripts/physics.js';
 import { i18n } from '@/i18n.js';
 import { instance } from '@/instance.js';
 import { defaultStore } from '@/store.js';
+import { miLocalStorage } from '@/local-storage.js';
 import * as os from '@/os.js';
 import { definePageMetadata } from '@/scripts/page-metadata.js';
 import { claimAchievement, claimedAchievements } from '@/scripts/achievements.js';
@@ -443,6 +446,21 @@ definePageMetadata(() => ({
 				z-index: 1;
 			}
 
+			> .iconAlt {
+				display: block;
+				width: 85%;
+				margin: 0 auto;
+				position: relative;
+				z-index: 1;
+			}
+
+			> .iconCredit {
+				margin: 0 auto;
+				width: max-content;
+				position: relative;
+				z-index: 1;
+			}
+
 			> .misskey {
 				margin: 0.75em auto 0 auto;
 				width: max-content;
diff --git a/packages/frontend/src/pages/about.vue b/packages/frontend/src/pages/about.vue
index e4391568008a..52672426216a 100644
--- a/packages/frontend/src/pages/about.vue
+++ b/packages/frontend/src/pages/about.vue
@@ -11,7 +11,9 @@ SPDX-License-Identifier: AGPL-3.0-only
 			<div class="_gaps_m">
 				<div :class="$style.banner" :style="{ backgroundImage: `url(${ instance.bannerUrl })` }">
 					<div style="overflow: clip;">
-						<img :src="instance.iconUrl ?? instance.faviconUrl ?? '/favicon.ico'" alt="" :class="$style.bannerIcon"/>
+						<img v-if="miLocalStorage.getItem('kawaii')" src="/client-assets/kawaii/misskey-io.png" alt="" :class="$style.bannerIconAlt"/>
+						<img v-else :src="instance.iconUrl ?? instance.faviconUrl ?? '/favicon.ico'" alt="" :class="$style.bannerIcon"/>
+						<Mfm v-if="miLocalStorage.getItem('kawaii')" text="Logo by @sawaratsuki@misskey.io" :class="$style.iconCredit"/>
 						<div :class="$style.bannerName">
 							<b>{{ instance.name ?? host }}</b>
 						</div>
@@ -168,6 +170,7 @@ import { i18n } from '@/i18n.js';
 import { definePageMetadata } from '@/scripts/page-metadata.js';
 import { claimAchievement } from '@/scripts/achievements.js';
 import { instance } from '@/instance.js';
+import { miLocalStorage } from '@/local-storage.js';
 
 const props = withDefaults(defineProps<{
 	initialTab?: string;
@@ -230,6 +233,12 @@ definePageMetadata(() => ({
 	border-radius: 8px;
 }
 
+.bannerIconAlt {
+	display: block;
+	margin: 16px auto 0 auto;
+	width: 85%;
+}
+
 .bannerName {
 	display: block;
 	padding: 16px;
@@ -238,6 +247,13 @@ definePageMetadata(() => ({
 	background: linear-gradient(transparent, rgba(0, 0, 0, 0.7));
 }
 
+> .iconCredit {
+	margin: 0 auto;
+	width: max-content;
+	position: relative;
+	z-index: 1;
+}
+
 .rules {
 	counter-reset: item;
 	list-style: none;
diff --git a/packages/frontend/src/ui/_common_/navbar.vue b/packages/frontend/src/ui/_common_/navbar.vue
index fa1f0eb8c77e..447f5838318e 100644
--- a/packages/frontend/src/ui/_common_/navbar.vue
+++ b/packages/frontend/src/ui/_common_/navbar.vue
@@ -9,7 +9,8 @@ SPDX-License-Identifier: AGPL-3.0-only
 		<div :class="$style.top">
 			<div :class="$style.banner" :style="{ backgroundImage: `url(${ instance.bannerUrl })` }"></div>
 			<button v-tooltip.noDelay.right="instance.name ?? i18n.ts.instance" class="_button" :class="$style.instance" @click="openInstanceMenu">
-				<img :src="instance.iconUrl || instance.faviconUrl || '/favicon.ico'" alt="" :class="$style.instanceIcon"/>
+				<img v-if="miLocalStorage.getItem('kawaii')" src="/client-assets/kawaii/misskey-io.png" alt="" :class="$style.instanceIconAlt"/>
+				<img v-else :src="instance.iconUrl || instance.faviconUrl || '/favicon.ico'" alt="" :class="$style.instanceIcon"/>
 			</button>
 		</div>
 		<div :class="$style.middle">
@@ -68,6 +69,7 @@ import { $i, openAccountMenu as openAccountMenu_ } from '@/account.js';
 import { defaultStore } from '@/store.js';
 import { i18n } from '@/i18n.js';
 import { instance } from '@/instance.js';
+import { miLocalStorage } from '@/local-storage.js';
 
 const iconOnly = ref(false);
 
@@ -173,6 +175,11 @@ function more(ev: MouseEvent) {
 		aspect-ratio: 1;
 	}
 
+	.instanceIconAlt {
+		display: inline-block;
+		width: 85%;
+	}
+
 	.bottom {
 		position: sticky;
 		bottom: 0;