Transient teacher from the world of Wa no Kuni. He is a master of the Iga ninja corps and has come to pass on that wisdom and experience to the next generation. He specializes in body double arts above all others. His body double does not refer to moving so fast it looks to people as if there are several people present, but a secret technique where he is literally splitting himself apart and have his living body parts move in tandem. As a result of this, binding techniques and cutting attacks are mostly useless against him. Sandayu isn't actually human, but a rokurokubi or a type of ghost from another land known as a hitouban. He's the type of teacher who gladly teaches his techniques and knowledge to others. He often wanders from school to school wherever many problems arise and vacancies crop up. He likes students with strong competitive spirits that try to surpass their masters. And due to his experience from his home world, he has great sympathy for those who have lost their leaders.
