The My Stepmom’s Daughter Is My Ex anime, an adaptation of the romantic comedy light novels by Kyousuke Kamishiro, is set to premiere sometime in 2022. A visual and teaser trailer have been released.
It was also revealed that the anime is produced by Project No.9 and directed by Bottom-tier Character Tomozaki’s Shinsuke Yanagi. Deko Akao (The Case Study of Vanitas) is the series composer and scriptwriter, while Katsuyuki Satou (Higehiro: After Being Rejected, I Shaved and Took in a High School Runaway chief animation director) is the character designer.
On the cast side, Rina Hidaka and Hiro Shimono are playing the roles of main characters Yume Irido and Mizuto Irido respectively.
The My Stepmom’s Daughter Is My Ex light novels, which feature illustrations from Takaya-Ki, began in 2018 and have seven volumes as of July 2021. The books are published under the Kadokawa Sneaker Bunko label.
My Stepmom’s Daughter Is My Ex began life in 2017 as a web novel that was published on Kadokawa’s Kakuyomu website. The light novels inspired a manga adaptation in 2019.
J-Novel Club describes the light novels as:
Ah, high school. Is there any better place to start fresh after a horrible middle school relationship? Nope! Not unless your ex ends up at the same school as you and is now your stepsibling. What was supposed to be a sanctuary of peace where I could avoid ever seeing her again has become a living nightmare! Everywhere I look, I see her—in my house, in my school, in my class. There’s no escape! She even claims that she’s the older sibling. Like hell she is! But I won’t lose to her. After all, I’m the older brother in this new family situation. That’s right, we’re family now. No matter how much we may have thought we loved each other before, we saw one another’s true colors and realized we weren’t meant for each other. That’s why even though we may keep up a buddy-buddy sibling act for the sake of our parents, things will never go back to the way they used to be.