Seiji is a very arrogant magus who can be boastful and proud at times. His biggest flaw is that he is extremely overconfident and not very cautious which causes him to die accidentally, early on in the Holy Grail War.
He has shoulder-length black hair.
Fate/Prototype: Fragments of Sky Silver Edit
Seiji Jinga was the master of Assassin during the 1991 Tokyo Holy Grail War.
Day 1 Edit
On the first day of the tournament, Seiji summons Assassin in an abandoned warehouse in the Tokyo Port area. Going up to Assassin, Seiji gets instantly captivated by her allure and despite Assassin being not very conscious, makes the mistake of kissing her. Seiji then dies by Assassin's Zabaniya: Delusional Poison Body making him the first master to be killed in the 1991 Tokyo Holy Grail War, albeit accidentally.
Seiji is vastly inexperienced as a magus. While he does come from a magus family, he doesn't have much experience with dealing with magical beings like servants.