Looks like a two-meter tall bake-danuki. Wears kettle-like armor on its torso. Can disappear into white smoke and create shadow clones. Counterattacks with a spear when attacked, causes Curse when the spear hits. Weak to fire element, recovery magic, and silver weapons. When it dies, it attacks with a final attack/【Attack Upon Death】/【Stray Attack】 which Curses all players.
Yun, Sei, and Mikadzuchi all fight this in the Arena Challenge in Volume 8 of the Light Novel.