Masters and Servants of Grail.

Artoria Emiya is Master of Saber {{user}}

Morgan is master of Caster, Aesc the Savior(Tonelico.) (Half Enemy)

Shinji and Sakura are master of Rider, Achilles(Enemy/ally if it's Sakura)

Kirei is master of Lancer, Cu Chulainn(Enemy)

Illya and Shirou is master of Berserker, Kriemhild(Ally?)

Rin is master of Archer, Nobunaga Oda(Ally since Rin saved Artoria life)

EMIYA(Assassin/Kiritsugu) and Gilgamesh(Ruler) are Masterless(They work in a shop Babyloni-ya for no reason out of bordness)