Tamon’s B-Side Anime Reveals Key Kinoshita Family Cast: Runa Sasaki and Ayaka Nanase Board J.C.Staff Production

The television anime adaptation of Yuki Shiwasu’s romantic comedy manga, Tamon’s B-Side, has announced significant voice casting additions ahead of its scheduled January 2026 premiere. The production committee confirmed that Runa Sasaki and Ayaka Nanase are joining the ensemble cast, completing the core family unit of the series.

Sasaki is set to portray Homare Kinoshita, while Nanase will voice Yamato Kinoshita. These characters are the younger siblings of the passionate superfan, Utage Kinoshita. Their involvement is expected to enhance the emotional depth of the narrative by showcasing the familial support system surrounding Utage as she works to boost the confidence of her favorite idol.

Previously Announced Main Cast

This duo joins the previously announced main cast members: Saori Hayami as the enthusiastic Utage Kinoshita and Kakeru Hatano as the deeply insecure idol Tamon Fukuhara. The cast also includes Shoya Chiba (Ori Sakaguchi), Tasuku Hatanaka (Keito Tachibana), Kohei Amasaki (Natsuki Ishibashi), and Ryuho Nakaoka (Rintaro Kai).

The story of Tamon’s B-Side skillfully combines heartfelt romance with the challenging realities of idol culture. Key themes explored include perseverance, self-doubt, and the transformative influence of dedicated fandom.

Production Team and Studio

The series is being produced by an experienced creative team at the renowned animation house J.C.Staff. Chika Nagaoka is directing the project, with Chiaki Nagai handling the series composition. Yoko Ito, known for her work on titles such as Love Stage!!, is serving as both character designer and chief animation director. This seasoned staff aims to deliver a high-quality visual and narrative adaptation consistent with the acclaimed source material.

Yuki Shiwasu’s manga originated in Hakusensha’s Hana to Yume magazine, where it has been serialized since October 2021, resulting in twelve tankobon volumes as of October 2025. The series has received industry recognition, including a nomination for Best Shoujo Manga at Kodansha’s 47th Manga Awards and a top-ten placement in the 2023 Kono Manga ga Sugoi! guidebook. International fans can access the manga through Viz Media, which holds the English licensing rights.

Major producers Shochiku, Hakusensha, and King Records are backing the project. Furthermore, the in-story idol group F/ace has already engaged audiences with their insert song Supernova, setting the stage for a compelling debut early next year.