The main protagonist of the series. Despite his looks and easygoing personality, he is a capable and strong worker who works for Benika as a dispute mediator. When he was young, he lost his family in a terrorist attack. As a result, he became withdrawn from the world until he met Benika. He wished to be as strong as her so he could live on. Benika decided to leave him at the Hōzuki household. It was there that he trained his body extensively and learned Hōzuki-style martial arts. His kind demeanor attracts considerable attention from the opposite gender, though he is completely oblivious. In emergencies, he is able to produce a large 'horn' out of his right elbow which classes him as "Type 1 Class 2 Fighting Demon". This special weapon was designed for the purpose of assassination. This lets him use his full strength in combat, but shortens his lifespan. When he is forced to fight, his personality changes to a more aggressive one. Between the anime and the manga, there are differences in the way Shinkurō is depicted.

In the anime, Shinkurō is not as confident and appears to have less control over the Hozuki horn.