What is Nuclear Fusion?

Nuclear Fusion is a boss theme from the Touhou video game Subterranean Animism, composed by ZUN and released in 2008[1]. It serves as the battle music for the character Utsuho Reiuji and became popular in Japanese MAD video and remix culture.

Where did Nuclear Fusion come from?

The song originated in Touhou 11: Subterranean Animism, released at Comiket 74 on August 16, 2008[2]. It was created by ZUN as the Stage 6 Boss theme for Utsuho Reiuji.

What does Nuclear Fusion mean?

The full title "Solar Sect of Mystic Wisdom ~ Nuclear Fusion" references the boss character's power to manipulate nuclear fusion[1]. The song is associated with the iconic "☢ CAUTION!!" warning screen that appears before her spellcards.

How do you use Nuclear Fusion?

Creators use Nuclear Fusion as background music for MAD videos, remixes, and YTPMVs[1][5]. The song's energy and the ☢ CAUTION!! motif are often incorporated into video titles and visual elements.

Is Nuclear Fusion still popular?

Nuclear Fusion is a classic in Touhou remix culture. By 2011, over 600 videos using the song existed on Nico Nico Douga alone[1], and it is still referenced in Touhou fan communities and YTPMV compilations.

Nuclear Fusion

2008viral musicclassic

Published September 10, 2026

Nuclear Fusion is a boss theme from the Touhou video game Subterranean Animism that became a staple of Japanese MAD videos and remix culture. Composed by ZUN and released in August 2008, the song's intense energy and iconic "☢ CAUTION!!" warning screen made it a popular foundation for thousands of fan remixes and YouTube Poop Music Videos.

internet memes

Overview

Nuclear Fusion features a driving, intense electronic composition that builds tension throughout the boss fight. The track is distinguished by its association with a unique in-game warning screen: before Utsuho Reiuji's spellcards begin, the screen displays "☢ CAUTION!!" alongside radiation symbols while klaxons blare in the background1. This is the only boss warning of its kind in the Touhou series, making it a memorable and meme-able element.

The song's full title is "Solar Sect of Mystic Wisdom ~ Nuclear Fusion" (霊知の太陽信仰 ~ Nuclear Fusion), reflecting the character's nuclear-themed powers2. Remixes of the song commonly incorporate the "☢CAUTION!!☢" motif in their titles or visually reference the warning screen during the video1. The track became a favorite resource for MAD video creators on Nico Nico Douga due to its energetic tempo and the thematic hook of the nuclear warning.

Origin & Background

Platform

Touhou Video Game / Nico Nico Douga (viral spread)

Creator

ZUN

Date

2008

Nuclear Fusion debuted as the Stage 6 Boss theme for Utsuho Reiuji (nicknamed "Okuu") in Touhou 11: Subterranean Animism. The game was composed and developed by ZUN under the circle name Team Shanghai Alice, first released at the 74th Comiket on August 16, 20082 3. The character Utsuho is a Hell Raven who gained the power to manipulate nuclear fusion, and the song's title directly references her abilities.

The track was reuploaded to Nico Nico Douga shortly after the game's release. The earliest notable MAD video using the song, titled "Airmoto Sect of Soka," was posted on September 28, 2008, blending the Nuclear Fusion track with the Hissu Amoto San internet phenomenon1.

Nuclear Fusion

Overview

Origin & Background

How It Spread

Frequently Asked Questions

References (5)