Shinjirō is the Japanese manga artist and creator best known for writing and illustrating the action series Taboo Tattoo. He began his professional career not with a traditional manga apprenticeship but as an online illustrator. After posting his artwork on the internet, he caught the attention of a publishing editor who offered him the opportunity to draw manga professionally, a medium he had never worked in before. His artistic style is heavily influenced by cinema, particularly horror and gore, with Peter Jackson's early film Braindead cited as a significant inspiration.

Shinjirō is the sole creator of the original manga Taboo Tattoo, which was serialized in Media Factory's Monthly Comic Alive magazine from November 2009 to June 2017. The series was compiled into thirteen tankōbon volumes. The story follows a martial arts middle school student who receives a mysterious and powerful tattoo that draws him into an international conflict over ancient weaponized artifacts. This manga was adapted into a twelve-episode anime television series by the studio J.C.Staff, which aired from July to September 2016. The anime adaptation was directed by Takashi Watanabe.

Beyond Taboo Tattoo, Shinjirō created the original manga series Nosferatu, published in four volumes. He described this work as an effort to move away from the traditional supernatural vampire archetype, instead reimagining the creature from a biological perspective as a parasite. He has cited Sheridan Le Fanu's novella Carmilla as a primary literary inspiration for this series. In addition to his original creations, Shinjirō has worked on a commissioned manga adaptation of Fate/Zero, a prequel to the widely popular Fate/stay night series. He has stated that while he prefers drawing his own original stories, working on a well-known property like Fate/Zero was a positive learning experience that taught him the value of adhering to an established structure.

Shinjirō's works are characterized by a focus on dark fantasy, action, and horror. His narratives frequently explore grim and violent scenarios, and his artistic identity is deeply rooted in a fascination with criminal psychology and revenge stories. He has expressed a pragmatic approach to character survival, noting that his characters do not always survive, as creating a horrifying and cruel scenario is often central to his mission as a creator. His thematic focus on dark subjects and his cinematic, detailed artwork have defined his career, establishing him as a creator with a distinct voice within the seinen demographic. His manga Taboo Tattoo has been licensed for English release in North America by Yen Press, and his works have been published in French as well, contributing to his international recognition.