Power/Ability post.
Well, I think it might be handy for some people to know what they're getting into when they mess with Iori, so, an ability list.
Yagami/Yasakani Martial Arts: Iori is the heir to an ancient Japanese family, and so, was trained in the martial arts. He also has a near beastial instinct and could possibly fight blind/deaf. His martial arts, in addition to making his body the peak of human perfection, allow him to cut things like flesh and cloth and maybe stone. With his bare hands.
Yagami Flame: If his martial arts weren't bad enough, Iori can produce a blue flame at will (this might be limited later). Besides having all the effects of a normal fire, this blue flame has an adverse effects on demons, weakening their powers and possibly giving him the ability to help seal them away. He has a jewel inside of him that gives him these powers which can be removed by someone with certain abilities. (Ash Crimson, possibly some demons.)
The Riot of Blood: Finally, Iori can enter the Riot of Blood if egged on enough or someone uses enough of a certain type of demonic power around him. Obviously, not all demons can match Orochi's 'wave-length' or Iori would be Rioting all over the place. When he enters this mode, he's completely unreachable by words and loses all ability to reason. His breath becomes visable, his physical strength goes up, and he's extremely fast. Literally, he's a monster like this. He was able to take Kyo Kusanagi by surprise and their teammate, and nearly killed them both. Easily.