He's one of the Dokusasako Castle ninjas, though his real name has never been revealed—he just goes by "Dokusasako's Resourceful Ninja" at this point, and honestly, even he introduces himself that way now. The nickname stuck because it actually fits. He's genuinely one of the most capable villains the series has thrown at the protagonist, and fans often note his competence sets him apart from a lot of other antagonists in the show.
Content compiled by AnimeList.moe from publicly available sources.
