Hirotsugu Ryusen is a Japanese writer recognized as the original creator behind the light novel, manga, and anime franchise She Professed Herself Pupil of the Wise Man (Kenja no Deshi o Nanoru Kenja). Ryusen began the series as a web novel published on the user-generated website Shōsetsuka ni Narō in April 2012. The series was later acquired for print publication by Micro Magazine, which released the first volume of the light novel under its GC Novels imprint in June 2014, with illustrations by Fuzichoco. As of December 2025, the light novel series has reached twenty-three volumes.

The success of the light novel led to multiple manga adaptations. The primary manga adaptation, illustrated by Dicca Suemitsu, began serialization in Micro Magazine's Comic Ride website in July 2016 and has been compiled into multiple tankōbon volumes. Two spin-off manga series have also been produced: Kenja no Deshi o Nanoru Kenja: Mira to Sutekina Shōkan Seirei-tachi, illustrated by Yu Uonuma, which began serialization in DeNA's Manga Box in October 2020, and Kenja no Deshi o Nanoru Kenja: Mariana no Touki Hi, illustrated by Vanilla Boww, which began serialization in Comic Ride in February 2021. All manga adaptations credit Ryusen Hirotsugu as the original writer.

The franchise expanded into animation with a twelve-episode anime television series produced by Studio A-Cat, which aired from January to March 2022. Ryusen is credited as the original creator of the work on which the adaptation is based.

Throughout these various media, the creator has remained consistently credited for originating the story and world of She Professed Herself Pupil of the Wise Man, establishing the series as the primary and most documented work associated with the name. Information on other original works by Hirotsugu Ryusen is not documented in available sources.