Fate/Zero

Kiritsugu Emiya, a ruthless mercenary known as the Magus Killer, enters the Fourth Holy Grail War on behalf of the Einzbern family, summoning Saber, the spirit of King Arthur, as his Servant. Seven magi and their summoned Heroic Spirits battle across Fuyuki City for the Holy Grail, a chalice said to grant any wish. Kiritsugu's pragmatic, ends-justify-means approach puts him at odds with Saber's chivalric code as rival Masters and Servants close in.