Nishiura (智仁 Nishiura) was young boy who became the Machete Mask. He was also best friends with Nakazaki.
Under the influence of the mask he aimed to make people kill themselves by jumping off buildings. And would directly kill a target since there wasn't a place where they could throw themselves of a building.
He wielded a machete, and appeared to be proficient in using it, as he used it to kill Nomura. While wearing the mask he was shown to have enhanced speed.