The Holy Grail is a legendary treasure that can fulfill all wishes of the bearer. The ceremony to obtain the Holy Grail is called the Holy Grail War.
The seven magicians chosen by the Holy Grail who participated in the Holy Grail War are called Masters, and they make contracts with seven familiars called Servants. They are seven Heroic Spirits selected by the Holy Grail, divided into seven classes, and summoned as Familiars. Only one group can obtain the Holy Grail, and each of these seven groups kills each other in order to become the last group.
Emiya Kiritsugu's adopted son, Emiya Shirou, accidentally made a contract with Saber, the swordsman in the Servant, and was involved in the Holy Grail War.
