Nobara no Otoko

Father of Isami.
Kai who was the physicist who was researching mystery material "Ruminotait" is missing five years ago.

He is chased to Kurotengu. he binds his head with a bandage, he put on one's sunglasses, and he wears a coat to hide his identity.
He has presented Isami the brier on her birthday.
His combat skill is also high because Kai piles up the training of Rumino Ninjutsu.