Saya

Saiya is the sheath spirit of the Demon sword Sou'unga. He is the spirit which is supposed to guard Sounga and stop the sword from being drawn.

He is a slacker and is said to be unreliable since he didn't hold Sounga as long as he was supposed to. This was around one thousand years.

He often tells people that bad things will happen after they already have, cementing the belief that he cannot be trusted with anything important.