Anime Adaptation Confirmed for 'Koishita Hito wa' Light Novel, Premiering Spring 2026

TO Books officially confirmed the anime adaptation for Mizuki Nagano's hit light novel series, Koishita Hito wa, Imouto no Kawari ni Shindekure to Itta. The adaptation is set to premiere in April 2026, arriving at a high point for the franchise.

The story, which translates roughly to The Person I Loved Asked Me to Die in My Sister's Stead, centers on Lady Wisteria. Desperate to be worthy of the man she loves, Lord Bright, Wisteria takes the place of her younger sister, Rosalie, in an arranged marriage. This choice sends Wisteria to serve as a guardian in the poisonous Predawn Realm.

Two decades pass before Wisteria's isolated life is thrown into chaos. A stranger who looks strikingly familiar appears, demanding a sacred sword.

The franchise has reached significant commercial success, moving over 1.1 million copies across print and digital formats. Nagano first serialized the story online starting in November 2020 before TO Books began publishing the print version in September 2021, featuring illustrations by Saori Toyota.

Critical reception has also been strong. The series consistently placed in the top ten of the Kono Light Novel ga Sugoi! rankings, securing the number-one spot in 2024.

This is not the first expansion for the property. A manga adaptation by Maki Yamori launched on TO Books' Corona EX platform in June 2022 and currently spans six volumes. Tokyopop holds the English license for the manga, with Volume 4 scheduled for release in August 2025.

Furthermore, a drama CD debuted in August 2024. The second drama CD is dropping today alongside the release of the eighth light novel volume.