Ascendance of a Bookworm Returns With WIT Studio for Season 4

Ascendance of a Bookworm has returned for its fourth season, subtitled Adopted Daughter of an Archduke, premiering on April 4, 2026. The beloved isekai series about a book-obsessed girl reborn into a medieval fantasy world is now in the hands of WIT Studio, marking a major production shift from the previous seasons animated by Ajia-do Animation Works.

A New Studio Takes the Reins

WIT Studio, known for its work on Attack on Titan's first three seasons, Vinland Saga, and Spy x Family, has taken over animation production for the fourth season. Yoshiaki Iwasaki steps in as director, replacing Mitsuru Hongo who directed the previous three seasons. Mariko Kunisawa returns to handle series composition, providing continuity on the writing side. Aiko Minowa serves as character designer, and Michiru continues composing the musical score.

The studio change is accompanied by a commitment to an extended run. Season 4 is confirmed to air across two consecutive anime seasons without a midseason break, giving the adaptation a full half-year of episodes to cover the Adopted Daughter of an Archduke arc.

The Story So Far

The series follows Myne, a young woman who dies and is reborn as a frail child in a world without books. Driven by her obsessive love of reading, she sets out to create books from scratch using whatever knowledge she retained from her previous life. The first three seasons traced her journey from a powerless commoner to a figure of increasing influence within the world's rigid social hierarchy.

In Season 4, Myne has adopted the name Rozemyne and begun her new life as the adopted daughter of Ehrenfest's archduke. She must navigate rigorous etiquette and magic training on top of her existing duties as High Bishop and forewoman. The High Priest has offered her access to the temple's book room, fueling her drive to expand the printing industry she helped create.

Seven New Cast Members

The fourth season introduces seven new voice actors to the expanding cast, reflecting the broader world Rozemyne now inhabits as a member of the noble class. The returning cast continues to anchor the series around Rozemyne's core relationships.

Streaming

Ascendance of a Bookworm Season 4 streams on Crunchyroll, continuing the platform's long-standing relationship with the franchise. For fans of the series, the combination of WIT Studio's animation pedigree and the extended two-cour format represents the most ambitious production the adaptation has received to date.