The anticipated Spring 2026 anime season marks the return of one of the most beloved isekai of all time, Ascendance of a Bookworm Season 4. The anime is loved for its incredible world-building and a slice-of-life approach to the isekai genre rather than an action fantasy. Ajia-do studio produced the first three seasons of the anime, but the latest season was picked up by WIT Studio, one of the most renowned animation studios in the country. Unfortunately, it was caught up in a major controversy this season when fans noticed the use of generative AI in the opening theme of Ascendance of a Bookworm Season 4, which left them disappointed. The anime’s latest season debuted on April 4th, 2026, and less than a week after the episode was out, the studio took full responsibility for the situation.
The opening theme has now been fixed, and the anime continues streaming new episodes every Saturday at 2:30 A.M. PT. While the subbed version has released three episodes so far, the English dub also made its debut on April 18th, 2026. The dub will be released at the same time, although it will be a couple of weeks behind the original version. The official website of Crunchyroll unveils the cast and crew and confirms the English voices behind the main characters have returned in this season as well.
Ascendance of a Bookworm Has Now Updated The Controversial Opening
Image Courtesy of WIT Studio
The studio is known for many beloved and acclaimed shows, especially the first three seasons of Attack on Titan. Over the years, WIT Studio has released several visually striking series such as Moonrise, Love Through a Prism, Vivy: Fluorite Eye’s Song, and more. Which is why the AI controversy baffled fans, but the initial disappointment is finally beginning to die down.
After confirming that generative AI was used to create certain cuts in the background art, the studio replaced the opening theme with an updated version after incorporating the redrawn background art assets. The studio also confirmed they do not authorize the use of generative AI in any of its projects. It also clarified that neither the art director nor the background production studio had any involvement in the matter. Luckily, the anime episodes don’t face the same criticism, and the irregularities in the art style are limited to the opening theme, which is now updated.
What Is Ascendance of a Bookworm About?
Image Courtesy of WIT Studio
The story centers around Urano Motosu, who loves books more than anything. Just when she was about to start her dream job of becoming a librarian, she died in an accident. As she takes her final breath, she wishes for nothing else but to read more books in her next life. She wakes up in an unknown world as Myne, a frail five-year-old girl. However, although she got a second chance at life, she is frustrated by the lack of books in a world without a printing press.
Since books have to be written and copied by hand, they are so expensive that only nobles can afford them. And thus begins Myne’s journey as a bookworm as she strives to read and make more books. The latest Season 4 follows her after she leaves her commoner life behind and becomes Rozemyne, a noble daughter of Ehrenfest’s archduke.
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