Anime: Fate/Zero, Fate/Stay Night
A.K.A.: Magus Killer
Age: 29 (34 in FSN)
Children: Illyasviel von Einzbern (Biological daughter), Shirou Emiya (Adoptive son)
Holy Grail War Participation: Fourth
When he was young he killed his own father for using terrible magic and destroying the town. He is taken in by Natalia Kaminski and taught how to kill. Thus he is great with weapons. He was hired by the Einzbern family to fight for them in the fourth Holy Grail War. He fights in the war to end all conflict. To do this, though, people must die. He refuses the Grails answer and chooses to use Saber to destroy the Grail. He finds Shirou in the destruction and takes him in as his own son. He is cursed with Angra Mainyu and passes away at 34.
Check out this AMV tribute to Emiya Kiritsugu: