Tetsusai Shishio

Tetsusai Shishio (志々尾 鉄斎, Shishio Tetsusai) is the father of Gen Shishio and the head of the Shishio family.

Appearance
In the manga, he has a noticeably larger build and his hair is white.

Personality
He is a stern but caring father who was greatly troubled by the numerous complaints against Gen that he agonized over his decision to send Gen away.

History
Tetsusai and Mrs. Shishio frequently had to apologize to their neighbors because Gen Shishio was constantly in trouble for fighting (although this was because other children picked on him). Tetsusai was worried that Gen was too quick to use violence. After Gen injures the neighborhood chairman, Tetsusai orders his other sons to bring Gen home while he, his wife and Ryo Shishio go the chairman's home. Instead Gen overpowers his brothers, leaving them traumatized, and Tetsusai reluctantly decides to send Gen away to the Shadow Organization for training. Gen overhears he and Ryo discussing this and the supposed betrayal triggers his full Ayakashi transformation, after which he runs away from home.

Plot
At Gen Shishio's funeral, Tetsusai recognizes that Masamori Sumimura accepted Gen under their conditions, but he asks him to leave to avoid further upsetting the family, especially Ryo Shishio.

Etymology

 * The name Tetsusai means "iron" (鉄) (tetsu) and "religious purification/purification, Buddhist food, room, worship, avoid, alike" (斎) (sai).

Trivia

 * Tetsusai named his son Gen (limit) so that he would understand his own limits.
 * In the Viz Manga, Tetsusai's name was written as Tessai Shishio.