I am thinking that perhaps the teacher from the movie was one of Seiko Fujita's students that he taught in WW II, mentioned in The Last Ninja Clip, and maby attained the title of Shidoshi ( teacher of the warrior ways of enlightenment) or perhaps a San-Dan (3rd degree) in belt rank or perhaps higher as he has his own school. What does everyone else think ?

That's my speculation, because in the clips you can see portrait of Seiko Fujita on the wall. Not sure how detailed they'll explain about the Fujita in the film though - I'm hoping they explain as much as they did in the last ninja clip.

I am also speculating that from their high degree of training Masazuka & Casey are his senior most students which means like his mentor and his mentor before him, he would have revealed to either of them depending on which one was the better of the two, more Koga Style Ninjutsu secrets/techniques than he would have a regular student, such as The Yoru Bitsu.

His name is Sensei Takeda (as that was his daughters last name..) and apparantly he reached a high enough rank to become soke or head of the family for his school which he had presided over for close to 40 years..