A blind hitokiri in Takasugi's employ, Nizou shares his boss's destructive worldview—he wants to tear everything down. His swordsmanship is absurdly good; he can cut someone without even unsheathing his blade, which is exactly as broken as it sounds. That said, Gintoki managed to snap his sword during their first fight, which didn't sit well with Nizou.
When Nizou came back for round two, he'd upgraded to the Benizakura, a demonic blade that fused with his arm and gradually took over his body like some kind of parasite. As the sword consumed him, his upper torso got replaced with cybernetic modifications, and he devolved into little more than a mindless monster. Gintoki eventually put him down, though what actually happened to Nizou after that is unclear—he's pretty much assumed dead given how thoroughly the Benizakura had ravaged him.
His character draws inspiration from Okada Izō, a real hitokiri from the Bakumatsu period.
Content compiled by AnimeList.moe from publicly available sources.
