|Manga Debut||Chapter 16|
|Anime Debut||Episode 21|
|List of Characters|
A young sick man that lived near Chizu Sakanaka when she was younger.
He was sick for some unknown reasons and was be bedridden all the time. He played with Chizu as she was an only child with busy parents.
One say, when his health deteriorated fast, Chizu fed him a vial of what she believed was mermaid blood. Not long after that, he was transferred to a faraway hospital, and recovered, but never returned.
Later, in the present day, his grandson has the exact same appearance as his grandfather. That is the reason why Chizu thinks Keiichi has stayed young (immortal).