There is a legend of a Holy Grail which will make your wishes true. To gain this powerful Holy Grail, there is a ritual where it chooses seven masters and seven servants. Servants are Saber, Lancer, Archer, Rider, Caster, Assassin, and Berserker. To qualify as a one to posses the Holy Grail. Master has to eliminate other servants to show he is the strongest one.