Music project RetBear will perform the opening theme song for the upcoming TV anime adaptation of In a World Full of Zombies I’m the Only One Who Doesn’t Get Attacked, official announcements revealed on October 10. The production timed its news reveal with World Zombie Day. Official statements confirmed that composer and Vocaloid producer Kairiki Bear will produce the track titled “No Reaction.” The series is scheduled to make its TV debut in January 2027 on AT-X. That broadcast puts the popular story onto TV screens for the first time [1].
RetBear Performs World Full of Zombies Anime Opening
The announcement marks the return of RetBear to television anime themes after nearly four years without a release, reuniting the music project with the animation industry ahead of the winter broadcast [2]. Fans can watch the main promo video on YouTube. Official teaser artwork gives audiences an early look at the TV project.
The new track carries the full title “No Reaction (unknown Vo: 0in)” and features a guest singer performing under the project’s anonymous concept. RetBear operates as a musical unit where Kairiki Bear writes the lyrics, builds the composition, and handles the musical arrangement while inviting a different guest vocalist for each individual release. The collaborators don’t reveal their real names in public credits, choosing instead to label every singer with an unknown Vo designation to keep the listener’s attention centered on the music itself. RetBear previously contributed two notable anime opening themes. They produced “Mannaka DEAD END (unknown Vo: 10fu)” for the TV series Black Summoner, and they followed with “Down Timer (unknown Vo: O2)” for REVENGER [1].
Digital streaming details haven’t been announced yet. Because distribution plans for the single are coming soon, listeners can expect streaming dates closer to broadcast for the project’s first new music since Down Timer arrived in January 2023 [2]. The music unit will share release dates on digital storefronts once schedules are set.
Kairiki Bear Produces New Track No Reaction
Composer Kairiki Bear leads the RetBear music project. Having built a massive following within the Vocaloid community, the producer created several standout songs that earned tens of millions of views on online video platforms and helped pave the way for anime collaborations. The producer’s reputation bridges internet music culture and anime soundtracks. Listeners often recognize the artist through fast-paced rhythms and memorable melodies that spread widely among fans of Japanese vocal synthesis [1].
Among the producer’s biggest releases, the hit song “Venom” has accumulated over 75 million views on YouTube, while “Darling Dance” stands at more than 49 million views on the same video platform. The overall channel numbers show broad reach [1].
Reporting from Honey’s Anime and Anime News Network noted that Kairiki Bear’s official YouTube channel has surpassed 480 million views, while OtakuKart reported the total at more than 470 million views based on the announcement details. Official social accounts operate on X, TikTok, and YouTube. These profiles share video previews and artwork updates for the project. By maintaining active channels on major social networks, the team gives followers a dependable place to track upcoming music drops, teaser visuals, and production notices as the winter broadcast approaches [2]. Listeners can also follow the RetBear social accounts to learn when full music previews and streaming links become available.
Manga Downloads Propel World Full of Zombies
The television anime adapts a popular digital manga. Official announcements confirmed that the source manga has recorded more than 9.5 million downloads and sold over 750,000 copies to date, counting both the core storyline and its related spin-offs [1].
The story follows an ordinary man who discovers that roaming zombies completely ignore him while society collapses around him, turning everyday survival into an unusual journey as he moves through deserted streets and meets other people. While upcoming broadcasts like the Overgeared anime shared their premiere windows with full cast lists, this production focused early announcements on its musical direction and animated teaser [2]. The teaser highlights that setting. Viewers can see how the animated scenes capture the apocalyptic tone of the original publication. Readers who followed the comic series will notice several familiar sequences brought to life in the teaser video [1].
Adapting a manga with millions of digital readers gives the TV project a strong public foundation as it prepares for the winter broadcast window. Fans can now see how the production translates the comic panels into animated scenes. Strong source sales provide encouraging signs for the series. The move from digital pages to TV broadcast brings the story to a much larger audience [1].
Anonymous Vocalist Concept Drives Unit Identity
Anonymity defines the RetBear aesthetic. Rather than relying on established celebrity singers, Kairiki Bear pairs high-energy electronic production with fresh vocalists who perform under unknown Vo codenames, assigning the label unknown Vo: 0in to the performer on “No Reaction.” This rotating format lets the unit reshape its vocal delivery for different series while keeping Kairiki Bear’s signature songwriting style recognizable on every release [1]. The project invites listeners to appreciate each vocal performance on its own terms without preconceptions based on prior fame.
The project debuted on television when unknown Vo: 10fu performed the opening theme for Black Summoner, followed in January 2023 by unknown Vo: O2 on “Down Timer” for the anime series REVENGER [2]. Each singer brought a distinct vocal texture.
The four-year hiatus between releases left listeners wondering when Kairiki Bear would revive the unit for another TV project. Now that World Zombie Day brought the news out into the open, fans can revisit earlier tracks while getting ready for the new broadcast [1]. The return ends a long wait. Because the unit pairs a different singer with each song, every release feels like a brand-new collaboration while maintaining the unmistakable musical foundation that Kairiki Bear brings to the studio. That balance between fresh voices and familiar production keeps the project appealing to anime fans.
Broadcast Window Sets World Full of Zombies Premiere
The TV adaptation of In a World Full of Zombies I’m the Only One Who Doesn’t Get Attacked will premiere in January 2027 on the AT-X network [1]. AT-X will handle the domestic broadcast run. The channel broadcasts new television anime series to Japanese viewers.
Distributed online with credits to FRONTIERWORKS, the main promo video and official key visual give audiences an early look at character encounters and the ruined urban backdrop that frames the adaptation [2]. It doesn’t spoil the story. Instead, the footage confirms the tone that readers expect to see on television. Viewers who watch the promo clip on YouTube can hear short audio cues that hint at the atmosphere of the series. The visual presentation focuses on the contrast between the wandering undead and the unharmed protagonist. The combination of animation and key art sets the stage for a memorable winter premiere [1].
With January 2027 still months away, details regarding additional cast members, production staff, and digital streaming platforms will arrive in future updates. For now, the opening theme reveal gives fans an exciting taste of what’s coming to TV screens next winter [1]. Listeners can follow the official RetBear accounts for further announcements.
- PRESS RELEASE Honey’s Anime. (2026, October 15). RetBear to perform, Kairiki Bear to produce OP theme song for In a World Full of Zombies I’m the Only One Who Doesn’t Get Attacked. [Article Link]
- ONLINE NEWS Jones, B. (2026, October 15). In a World Full of Zombies I’m the Only One Who Doesn’t Get Attacked anime reveals RetBear opening theme. OtakuKart. [Article Link]
- PRESS RELEASE Anime News Network. (2026, October 15). In a World Full of Zombies I’m the Only One Who Doesn’t Get Attacked OP theme song to be sung by RetBear. [Article Link]
