Sōichi Mogami

===Sōichi Mogami (最上 宗一) was a member of Border and Yūichi's mentor.===

Black Trigger Capture Arc
Yūma mentions him as the acquaintance his father had in Border. Rindō reveals that he died 5 years ago and put his life energy into Fūjin.

History
Sōichi was a formal Border Agent. He also was Yūgo's rival. He used his life to make a Black Trigger, the same trigger which Jin has right now. He used to be Jin's advisor.