Matamune is a Nekomata—basically a two-tailed cat spirit—who's been hanging around the Asakura family for literally a thousand years. He shows up in volumes 19 and 20 of the Shaman King manga, though anime-only fans won't see him since he never made it into the show.
The guy's pretty distinctive: he carries a pipe around and sports a necklace made of three bear claws (which Yoh eventually inherits). Despite his long history with the family, Matamune spends most of his time traveling and exploring the world. He's got this whole vibe of having seen absolutely everything—and he's almost always got his nose in a book. You know the type.
Content compiled by AnimeList.moe from publicly available sources.
