Sai no Oni

Sai no Oni are demons made of the tainted earth of the Shadowlands. They have a wide shell of lava on their back, and eight legs capable of moving at considerable speeds in comparison to their bulk. They are like large tainted turtles made of earth. Their skull is dense and sloping to protect their eyes, and their wide mouth is filled with blunt teeth used for crushing. They are essentially living battering rams, and as such are not particularily bright. They usually need smarter oni to give them orders, and very few will follow human orders except maybe from the person who summoned them. The sturdyness of Sai no Oni became quite a problem for the Crab Clan, who resorted to experimenting with jade-tipped arrows and bolts for their siege weapons, just to take out any Sai no Oni. (CoR3E p. 160)