Seiji Ebisu is a Japanese author recognized for his work in the light novel genre, particularly for romantic comedies centered on sibling relationships. He made his professional debut in 2014 when he won the Gold Prize at the 26th Fantasia Awards for his work Don't Have Illusions About Girls. This award served as a significant entry point into the industry, leading to his association with the Fujimi Fantasia Bunko imprint, a well-known publisher of light novels.

Ebisu is best known as the original creator of the series Ore ga Suki nano wa Imōto dakedo Imōto ja nai, which is also known as My Sister, My Writer. The story follows the lives of a brother and sister, Yuu and Suzuka Nagami, and involves a light novel award, a secret authorship, and the comedic complications that arise from their relationship. The first volume of the light novel series, featuring illustrations by Gintarō, was published in August 2016. The success of the light novels led to an expansion into other media. A manga adaptation, illustrated by Kō Narita, began serialization in Monthly Dragon Age magazine in December 2017. Subsequently, an anime television series adaptation produced by studios NAZ and Magia Doraglier aired from October to December 2018.

The creator's body of work is characterized by a consistent focus on youth-oriented romantic comedy with specific recurring narrative techniques. His stories often employ a first-person male perspective and generate dramatic conflict through identity deception or mistaken assumptions. The central relationship in his most prominent work explores a pseudo-sibling dynamic, where the plot hinges on the connection between a brother and sister who are not as they initially appear. This theme of blurred familial lines is further evident in his later work, a novel published in 2023 titled Left and Right Are Both My Little Sister, Which One Will My Older Brother Choose?, which continues his exploration of comedic scenarios involving sibling relationships and multiple female love interests.

In terms of industry significance, Ebisu's career demonstrates a typical trajectory for a successful light novelist in Japan, moving from a competition win to a long-running series and then to cross-media adaptations. The adaptation of My Sister, My Writer into a manga and an anime series represents a significant milestone, marking his entry into the broader anime and manga industry as an original creator. His work has maintained a dedicated readership, with his 2023 novel accumulating a notable number of online follows. While the anime adaptation of his work experienced production difficulties and received mixed technical reviews, its broadcast solidified his status as a creator whose source material was considered viable for major multimedia projects.