Kasai Tatsuyoshi

An executive of the Sonozaki Corps.

He often works for Shion as a chaperone.

He looks mild-mannered, but rumor says he's got many heroic stories from his youth.

He has a sweet tooth and is a heavy drinker.

It's suggested that Kasai was in a love triangle with Akane and the twins' father in the past, and though he lost in the end, Kasai still stuck around as their dad's friend. During the dam war Kasai went to get sniper training.