Iris Out

Kenshi Yonezu's single "Kick Back", used as the opening theme song for the anime adaptation of Chainsaw Man, saw global commercial success upon its release. Becoming the first song recorded in Japanese to receive a Gold certification from the Recording Industry Association of America (RIAA),^[1] "Kick Back" charted in various territories, including the Billboard Hot Rock & Alternative Songs chart, the UK Rock & Metal chart and the Canadian Hot 100.

In a press release on July 4, 2025, Kenshi Yonezu announced he recorded "Iris Out", the opening theme song for the Japanese animated film Chainsaw Man – The Movie: Reze Arc.^[2] On August 1, the release date of "Iris Out" was announced for September 24, as a double A-side single with an untitled song.^[3] The title for the untitled song was revealed on August 14, "Jane Doe", a collaboration single with Japanese-American singer Hikaru Utada.^[4] In a press release, "Jane Doe" was revealed as the ending theme song for the film.^[5]

"Iris Out" was digitally released on September 15, 2025. The song was later released physically on September 24, 2025, alongside "Jane Doe", as a double A-side single. Three variants were released: the regular edition, the Iris Out edition and the Jane Doe edition. The Iris Out variant includes an acrylic stand and a Polaroid photo of the character Reze from Chainsaw Man as bonus goods, while the Jane Doe version consists of a DVD of the "Kick Back" music video and a live performance video.^[6] First press bonuses for all variants include a serial number for a lottery in winning tickets to Yonezu's 2026 Ghost Tour.

A music video was released on September 15, 2025, on Yonezu's official YouTube channel, using footage from the film. Billboard Japan reported that it contains some spoilers from the movie.^[7]

Like "Sayonara, Mata Itsuka!", Yonezu debuted the song at the 76th NHK Kōhaku Uta Gassen. The performance, which was recorded at the former Tokyo Expressway,^[8] starts with him in a telephone booth, listening to Hikaru Utada's chorus from his other single, Jane Doe. He then walks toward a LED catwalk, alongside female dancers. Approximately 100 dancers participated in the performance. During the transition between the first chorus and second verse, he travels in a shark vehicle. He finishes the performance with the girl group Hana, as they thank viewers and wish for a happy new year, while fireworks can be seen in the distance.^[9][10]

"Iris Out" was also featured in the popular battle royale game Fortnite, where the audio was used as a "jam track" and users can purchase the song for 500 Vbucks.^[11][12]

• Digital download and streaming

1. "Iris Out" – 2:32

• CD

1. "Iris Out" – 2:31
2. "Jane Doe" – 3:55

• Jane Doe DVD

1. "Chainsaw Man – The Movie: Reze Arc" (trailer) – 1:29
2. "Kick Back" (music video) – 3:39
3. "Kick Back" (live video) – 3:13

• 12" Single

1. "Iris Out"
2. "Jane Doe"
3. "Kick Back"
4. "Kick Back" (Frost Children remix)
5. "Kick Back" (Hudson Mohawke remix)
6. "Kick Back" (Tomggg remix)

• Kenshi Yonezu – vocals, production, programming, arrangement
• Masahito Komori – mixing, engineering
• Randy Merrill – mastering