Shin Megami Tensei Apocrypha: War of the Dove

A standalone story set in the larger Megami Tensei universe. Our hero Hato is just an ordinary schoolboy, until one day he receives a ~~Command Spell~~ Stigma on his left hand, forges a contract with ~~Lancer~~ Cu Chulainn to become his master, and is unwittingly dragged into a city-wide Holy ~~Grail~~ War.