In the chapter 7, page 19, there is a person standing majestically on top of a flag pole, whose appearance is very similar to Ryu Hayabusa of the modern Ninja Gaiden game series. He is a monster since he is at Yōkai Academy, it is very likely that he is a member of the ninjutsu club and possibly also the head of it, if such a thing exists at the Yōkai Academy.