Argento Soma

The story of a young man named Takuto, whose life is ruined by an alien monster nicknamed "FRANK", as he killed the one Takuto loved, and severly wounded him. His life changes as well as his identity, which is now "Ryu Soma", who now works on a military service to seek and gain revenge on Frank (which is quite an obsession). However, this task he gave to himself is complicated by a young girl named Hattie Bartholomew, who not only befriends Frank, but ressembles Takuto's lost love.