Manabu Kai

Manabu Kai was a member of Old Border.

Appearance
In the picture found by Osamu, Kai appeared with a lab coat and a dark colored shirt with black jeans.

Personality
Not much is known about his personality.

Background
At a certain point in time before the start of the series, he joined Old Border. He later participated in the mission around five years ago which killed him and nine of his friends.

B-Rank Wars Arc
When asked by Osamu about the current whereabouts of the members of Old Border, Yuri points doesn't point out Kai as he was one of the ten who died.