Gilgamesh served as Kotomine’s Servant during the fourth Holy Grail War where he was known as his Servant class, Archer. He doesn’t serve Kotomine as a Servant, but rather as his partner. Gilgamesh is arrogant, egomaniacal, and megalomaniacal. He considers himself superior to everyone else and places himself above even gods. Gilgamesh has a special ability to act independently and to completely ignore his Master’s orders.

Typically clad in an ornate golden armor, he possesses an immense number of Noble Phantasms, though none are representative of his true identity. Because of this, no one could identify his true name. Gilgamesh met Saber during the fourth Holy Grail War and developed an obsessive interest in her.