Tetsuya Umesaki

Tetsuya Umesaki was a member of Old Border. He was the creator of the Black Trigger now used by Tsukihiko Amō.

Appearance
In the picture found by Osamu, Umesaki appears as a man in his early-mid 20s, with a stubble and very unkempt blond hair. He wears a dark purple sweater, with a purple undershirt as well as white pants.

Personality
Although almost nothing is known about Umesaki, his personality might be reflective of his Black Trigger, which is wildly destructive. It's possible his personality is similar to Amō's. At the very least, because of how Black Triggers work, their personalities should be compatible.

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 Umesaki as he was one of the ten who died.