The anime *In a World Full of Zombies, I’m the Only One Who Doesn’t Get Attacked* now has an opening theme. The song is titled “No Reaction (unknown Vo: 0in)” and is performed by RetBear. RetBear is a music project by Vocaloid producer Kairiki Bear.
This announcement came from FlyingDog, Inc. on World Zombie Day. The anime will begin airing in January 2027 on AT-X. The key visual and main promotional video for the anime have also been released.
RetBear's first new song in nearly four years
“No Reaction” is RetBear’s first new song in nearly four years. RetBear’s previous song was “Down Timer.” That song was released in January 2023.
For this song, RetBear once again featured an anonymous guest vocalist. The guest vocalist is credited as “0in.” This name appears in the song title as “unknown Vo: 0in.”.
RetBear wrote the lyrics, composed, and arranged this song. Streaming details for this song will be announced shortly.
Kairiki Bear, the Vocaloid producer behind RetBear
Kairiki Bear is a popular Vocaloid producer. Kairiki Bear is known for several hit songs, such as “Venom” and “Darling Dance.” The “Venom” video has reached 75 million views on YouTube. The “Darling Dance” video has reached 49 million views.
Kairiki Bear's YouTube channel has amassed more than 480 million views. Kairiki Bear is also known as one of the leading figures in the Vocaloid world.
Kairiki Bear is a composer and producer. RetBear is a music project founded by Kairiki Bear.
An adaptation of a manga with 9.5 million downloads
This anime is an adaptation of the manga *In a World Full of Zombies, I’m the Only One Who Doesn’t Get Attacked*. The manga has been downloaded more than 9.5 million times. Sales have also exceeded 750,000 copies. These sales figures include the spin-off series.
The anime adaptation will air on AT-X starting in January 2027. The song “No Reaction” by RetBear will serve as the opening theme for the anime.
About RetBear
RetBear is an “anonymous” music group. The group features Kairiki Bear collaborating with a different vocalist on each song. Each guest vocalist performs under the anonymous name “unknown Vo.”.
Before “No Reaction,” RetBear had already written two songs for anime. The first song was Mannaka DEAD END (unknown, 10fu). This song is the opening theme for the anime *Black Summoner*. The second song is Down Timer (unknown Vo: O2). This song is the opening theme for the anime REVENGER.
With “No Reaction,” RetBear now has three songs for anime. The latest information about RetBear is available on their official account X, TikTok, and YouTube owned by RetBear.
In a World Full of Zombies, I’m the Only One Who Doesn’t Get Attacked: Main PV
