Wit Studio said it used generative AI in the opening for season 4 of Ascendance of a Bookworm and will replace the affected scenes with hand-drawn art. The updated version is set to appear with the second episode, which is expected to air on Crunchyroll on April 11, 2026.
The admission came after Twitter user ukloim posted on April 4, 2026 that generative AI assets appeared in the opening of the new season, which launched that same day. Wit Studio then removed the sequence from its official social media and YouTube channels and later apologized to fans and the original author of Ascendance of a Bookworm for what it called a failure in its quality control process.
The response matters because Wit Studio said it does not allow generative AI in its works, except for the experimental short The Dog & The Boy, which it said was used to test the capabilities of genAI. That puts the opening of a new season of a streaming anime at the center of a broader fight over how studios use artificial intelligence in production.
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Founded in 2012, Wit Studio has built a profile on projects including Great Pretender, Attack on Titan, My Deer Friend Nokotan and Spy x Family, and it is also working on the One Piece anime remake for Netflix. For now, the next step is simple: the studio says the opening will be redone by hand before the second episode goes live, turning the controversy into a test of whether it can fix the mistake as quickly as it admitted it.
