Serina and Suzuna's father

 was the leader of a village of ninjas.

History
The ninja's of his village were ordered by their clan lord to slay a yōkai. They were able to slay one yõkai easily, but soon an army of yõkai attacked them. Nearly everyone in the village, including the leader, was killed by the attacking yōkai. His final act was telling his two daughters to be strong.

Legacy
His daughters believed that he wanted them to become strong enough to avenge him and their fellow ninja villagers. They sought to learn the art of demon slaying from someone at the  yōkai taijiya village. When Sango learned the truth about them, she believed, through her recollection of her own father, that he meant for them to find happiness on their own.

Powers & Abilities
He was skilled in the ways of the ninja.

Trivia

 * only appeared in flashbacks.