My Stepmom's Daughter Is My Ex Light Novel Series Ends With 14th Volume
Kamishiro began serializing the story on the Kakuyomu website in August 2017. Kadokawa began publishing the story in print volumes with illustrations by Takayaki (Arifureta - From Commonplace to World's Strongest) in December 2018. The 13th volume shipped in October 2025. Rei Kusakabe launched a manga adaptation of the novels on Kadokawa's ComicWalker website in December 2019.
J-Novel Club licensed the light novel series, and it describes the story:
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.
The novels inspired an anime that premiered on AT-X and Tokyo MX in July 2022. Crunchyroll streamed the series as it aired.
Source: My Stepmom's Daughter Is My Ex series' X/Twitter account
Disclosure: Kadokawa World Entertainment (KWE), a wholly owned subsidiary of Kadokawa Corporation, is the majority owner of Anime News Network, LLC. One or more of the companies mentioned in this article are part of the Kadokawa Group of Companies.KioskNews shows a cleaned-up reading view extracted from the publisher’s page — the original always lives on their site, not ours.