Fate/Zero

There was once a Holy Grail War waged by Mages and Heroic Spirits in a town of Fuyuki. However, one Mage took advantage of the chaos of World War II to steal a Holy Grail. Several decades have passed, and the Yggdmillennia family, who took upon the Holy Grail as its symbol, defected from the Mages' Association. Furious, the Association sent forces to deal with the Yggdmillennia, but were defeated. With the Holy Grail system changed, war at an unprecedented scale breaks out.

Waking up in a strange virtual world with no recollection of the past, Hakuno finds himself forced to fight for survival in a war he does not understand for a prize beyond value; the opportunity to have one's wish granted. With only an enigmatic "Servant" by his side, Hakuno Kishinami will have to face both friends and foes in battles to the death in order to not only gain possession of a mysterious object known as the "Holy Grail," but also to find the answer to the most important question of all: "Who am I?"