Tessai is the Devil responsible for killing most of the Koga ninja team with Yurimaru. His special ability is to turn his entire body into stone, making him almost totally impervious. Not to mention that he is a mammoth. Along with the impervious skin and gargantuan size he has an extremely bad disposition and he's not afraid to show it.
Tessai had the mispleasure of being the first to meet Jubei, and Jubei wasn't too lucky either. Jubei saved Kagero from being attacked by Tessai, and that is something that this Devil would not soon forget.
Tessai's weapon of choice is an absolutely humungous double sided double edged sword that he hurls through the air like a boomerang, and he almost always seems to catch it.