Masato Jinbo Is Directing, Writing, and Producing In-House
The adaptation is unusually centralized. Masato Jinbo (The Quintessential Quintuplets Movie, The Rising of the Shield Hero Season 2) is credited with both direction and series composition, and the animation itself is being made at PartsCraft, the studio Jinbo founded in 2018. Hiroshi Yoneda rounds out the announced staff as character designer and chief animation director, according to Japanese entertainment news site Comic Natalie.
Jinbo says production is already underway, and in his announcement comment he promised to draw the siblings "vividly, and in fresh blood," a Japanese pun pairing senretsu (striking) with senketsu (fresh blood). Given that the entire main family is unkillable, the bloody half of that promise checks out.
The reveal came with a teaser visual showing all seven siblings and an announcement promo video assembled from panels of the manga. The video also includes voice actor Rikuya Yasuda's first recorded lines as Theo.
Seven Siblings Who Cannot Die
Millennium Family follows the Benfield family, seven siblings born in England who have been alive for more than a thousand years. After centuries scattered apart, they reunite and start living under one roof again, right as a mysterious organization that wants their immortality for itself pulls them into a fight. Theo, full name Theodore, is the family's fourth son.
Yasuda (Arisu Yamabuki in Tune In to the Midnight Heart) voices him, and his announcement comment played up the obvious age gap: Theo is "probably the physically oldest character of my voice acting career." He also joked that watching the show might make viewers kinder to their immortal friends.
Sho Kasugai has been serializing the manga in Young King Ours, a Shonen Gahosha magazine, since March 2021, and volume 9 hits Japanese shelves on July 30, 2026. In his comment, Kasugai thanked readers and the production team, and told fans to look forward to seeing the immortal siblings finally move and talk.
Looking Ahead
The series is set to air on TBS and other networks, but no premiere date or season has been announced yet. Theo is also the only sibling with a voice so far; the casting for the other six Benfields is the next reveal to watch, and the official site is where those announcements will land.
No international streaming partner has been announced. If you want to read ahead in English, Anime News Network notes that the manga is available digitally as Millennium Family through emaqi, the North American e-bookstore run by Orange.