Kaze-maru is one of the last ninja around, working as a VIP bodyguard. He's best known for making it to the Semi-Finals of the fourth test, where he faced off against Yusuke and came up short. He was among the many who sought out Genkai to learn her techniques.
Fighting-wise, he's got solid physical skills and could actually handle the Reigun better than Yusuke could at that point in the series. His signature weapons are tracker shuriken—they lock onto anything with reiki and won't stop hunting it down. Each shuriken tip is packed with gunpowder too, so they explode on impact, making them pretty effective overall.
(The English dub spells his name as Kazamaru.)
Content compiled by AnimeList.moe from publicly available sources.