Wisteria is an orphan girl living in a corner of the British Empire at the end of the 19th century.

Her life is desolate and bleak–until she encounters Marbas, a powerful but equally lonely immortal being with a furry appearance, hounded by hunters.

[14] On August 28, 2020, Seven Seas Entertainment announced the English language release of the manga starting on June 1, 2021.

[4][15][16] A nine-chapter special manga series by Hoshino, subtitled The Flame Knight, was serialized in Shogakukan's Sunday Webry website from January 8 to March 5, 2023.

[35] At Crunchyroll Expo 2022, it was announced that the series would be animated by Ashi Productions and directed by Yasutaka Yamamoto, with Kenichi Yamashita in charge of series composition and writing scripts along with Yamamoto and Sayaka Harada; Mina Ōsawa designing the characters and serving as chief animation supervisor along with Hikaru Suzuki; Kanta Suzuki designing the monsters; and Hiroaki Tsutsumi and Kana Hashiguchi composing the music.