Wit Studio has apologized after confirming fan suspicions that generative AI was used in the opening of Season 4 of its latest anime, Ascendance of a Bookworm. The studio, known for popular shows including Spy x Family and Attack on Titan (Seasons 1-3), has announced that future episodes of Ascendance of a Bookworm will feature a redrawn opening with the gen AI elements removed.
Based on Miya Kazuki’s light novel series about a trainee librarian reincarnated in a magical world, Season 4 of Ascendance of a Bookworm hit Japanese TV screens on April 4. However, eagle-eyed viewers were quick to claim that the isekai fantasy anime’s opening showed telltale signs of generative AI use, sharing their observations on Reddit and Twitter/X.
AI generated backgrounds in the opening of the new Ascendance of a Bookworm season. Very unfortunate. https://t.co/rbjknegFhr pic.twitter.com/V9CD6KIiMM
— ukloim (@ukloim) April 4, 2026
Today, Wit Studio issued an official statement addressing the matter. After conducting an internal investigation, the studio determined that gen AI was indeed used to create the assets for the background art in a portion of the anime’s opening. Wit announced that it will redraw the backgrounds of the affected shots from scratch. According to the studio, Ascendance of a Bookworm will get a final, gen-AI free version of the opening from Episode 2 onwards.
Continuing with its apology, Wit stated that “in principle, we have not permitted the use of generative AI in anime production in our works.” (Wit Studios noted that the only exception is The Dog & The Boy, a short created as a technological experiment back in 2023). It reassured fans that its investigation uncovered no other incidents of gen AI usage in Ascendance of a Bookworm.
In these circumstances, fans may rush to blame Nam Hai Art, the company which worked on the backgrounds for the opening. However, Wit Studios stated that Nam Hai “had no involvement in the incident.” Instead, Wit Studios’ statement blamed the blunder on its own production management and quality control systems. Wit Studios added that it will take this incident as an opportunity to revise its guidelines and production management systems to prevent similar incidents happening in the future. “As the production company behind this series, we would like to apologize to all fans and to all the people involved, including the original author,” it said.
Gen AI usage in anime is a contentious topic. Amazon removed its AI-generated English dub of Banana Fish soon after launch, in response to audience backlash that lambasted both the lack of human voice actors and the bad quality of the dub. The making of many anime series nowadays involves outsourcing different parts of the process to multiple companies (sometimes in different countries), making it difficult to keep tabs on aspects like gen AI usage. Perhaps this incident with Ascendance of a Bookworm will also prompt other anime producers to revise their monitoring and management methods to ensure that unauthorized gen AI usage does not slip through the net into the final product.
Verity Townsend is a Japan-based freelance writer who previously served as editor, contributor and translator for the game news site Automaton West. She has also written about Japanese culture and movies for various publications.
