New visual, theme songs also announced
The official website of Betrothed to My Sister’s Ex, the television anime adaptation of Tobirano’s Zutaboro Reijō wa Ane no Moto Konyakusha ni Dekiai Sareru novels, revealed on Friday in a second promotional video that the series will debut on television on July 4. The staff also revealed more cast, a new visual, and the theme song information.

© とびらの・仲倉千景/双葉社・「ずたぼろ令嬢」製作委員会
krage performs the opening theme song “Gesshoku” (Lunar Eclipse), and Myuk performs the ending theme song “Marie.” The above video previews the opening theme. The commercial video below previews the ending theme.
The anime will debut on MBS, TBS, and CBC late at night on July 4 (technically on July 5 at 1:53 a.m.). The series will also air on BS-TBS.
New cast includes:
Minami Tanaka as Anastasia, the eldest daughter of Baron Shederan and Marie’s older sister

© とびらの・仲倉千景/双葉社・「ずたぼろ令嬢」製作委員会
Ryōhei Kimura as Louisphon, Kyuros’ school friend and the third prince of the Diltz Kingdom

© とびらの・仲倉千景/双葉社・「ずたぼろ令嬢」製作委員会
Yōko Hikasa as Mio, the head maid at Kyuros’ estate and a guard

© とびらの・仲倉千景/双葉社・「ずたぼろ令嬢」製作委員会
Sayaka Ōhara as Ryu-Ryu, Kyuros’ mother

© とびらの・仲倉千景/双葉社・「ずたぼろ令嬢」製作委員会

© とびらの・仲倉千景/双葉社・「ずたぼろ令嬢」製作委員会
The anime will star Rena Motomura as Marie and Daiki Hamano as Kyuros.
Takayuki Kitagawa (Tokyo 7th Sisters: Bokura wa Aozora ni Naru, episode director for The Quintessential Quintuplets ∬) is directing the anime at LandQ studios. Masakazu Sunagawa (Tokyo 7th Sisters: Bokura wa Aozora ni Naru, episode director for Mobile Suit Gundam: The Witch From Mercury) is the assistant director. Kenta Ihara (Ishura both seasons, Blue Miburo, Saga of Tanya the Evil) is both writing and overseeing the series scripts, Akiko Satō (Trigun Stampede, A Condition Called Love) is designing the characters, and Kujira Yumemi (Kubo Won’t Let Me Be Invisible, Dahlia in Bloom: Crafting a Fresh Start With Magical Tools) is composing the music.
Chikage Nakakura launched a manga adaptation on Futabasha’s Gaugau Monster website in July 2020. Futabasha published the manga’s eighth compiled volume on December 25.
Comico’s English website and app Pocket Comics is publishing the manga in a full-color vertical-scrolling version under the title Betrothed to My Sister’s Ex, but has not updated the series since November 2023. The black-and-white manga version in Japanese is ongoing.
Tobirano debuted the web novel on the Shōsetsuka ni Narō (Let’s Become Novelists) website in October 2019. Futabasha began publishing the light novels with illustrations by Mai Murasaki in April 2020, and it released the eighth volume on January 10.
Seven Seas Entertainment announced in April that it had licensed the light novel series and the manga, and will release them both starting in January 2026. The company describes the story:
Marie has spent her life living under her sister’s shadow as the two grew up in an impoverished baron’s home. Every nice thing went to Marie’s sister, leaving her without even a proper dress! And right when her sister was being married off to a wealthy Earl–tragedy strikes and Marie’s sister is killed en route. With the dowry already spent, it’s decided that Marie will take her sister’s place and become the Earl’s betrothed. But, when she gets there, she finds there’s been a serious mix-up—the proposal was a total misunderstanding! Can Marie win the heart of the handsome Earl, or is she destined to live a life without a single nice thing?
Sources: Betrothed to My Sister’s Ex anime’s website, Comic Natalie