Kyosuke Kamishiro is a Japanese author from Kyoto known for creating light novel and manga works, most notably as the original creator of the series My Stepmom's Daughter Is My Ex. His professional career began in 2014 when he received an honorable mention at the first Shueisha Light Novel Newcomer Awards for his work Witch Hunt Curtain Call: A Super Historical Murder Case. This early recognition led to the publication of his first light novels under Shueisha's Dash X Bunko imprint. However, his mainstream success arrived through his online writing activities. In 2017, he began serializing a web novel on the Kakuyomu platform titled My Stepmom's Daughter Is My Ex, which was originally known in Japanese as Mamahaha no Tsurego ga Motokano Datta. The series gained substantial popularity and won the grand prize in the love comedy category at the third Kakuyomu Web Novel Contest in 2018.

The success of the web novel led to a print light novel adaptation published by Kadokawa under their Sneaker Bunko imprint, with illustrations provided by Takayaki. The series centers on two former middle school sweethearts who unexpectedly become step-siblings after their parents remarry, forcing them to navigate their unresolved past feelings while living under the same roof. The light novel series proved commercially successful, being ranked third in the new works category of the Kono Light Novel ga Sugoi 2020 guidebook published by Takarajimasha. As the series expanded, it generated multiple adaptations across different media. A manga adaptation illustrated by Rei Kusakabe began serialization in 2019. This was followed by an anime television adaptation produced by the studio Project No.9, which aired in 2022, further cementing the series as one of Kamishiro's signature works.

Beyond his most famous series, Kamishiro has authored several other light novel series across different publishers. Under Kadokawa's MF Bunko J imprint, he wrote the series Do You Think Someone Like You Could Escape After a Reincarnation, Brother? and the Sherlock Academy series. With the publisher Shueisha, he also released the standalone title The Strongest Couple's Fluffy VRMMO Life: A Hot Spring Trip. Another notable work is I Will Solve Your Mysteries, published under the Seikaisha FICTIONS imprint. Kamishiro's body of work demonstrates a recurring focus on romantic comedy dynamics, often placing characters in ironic or high-concept situations such as former lovers becoming family members or interpersonal conflicts complicated by extraordinary premises like virtual reality gaming. His career trajectory, beginning with traditional light novel contests and transitioning through successful web novel serialization, reflects the contemporary path many Japanese creators take to achieve mainstream recognition in the anime and manga industry. While primarily recognized as a light novel author, his work serves as the foundational source material for manga and anime productions, establishing him as an original creator within the broader ecosystem of Japanese media franchising.