Fate/Stay Night
When Shirou is drawn into the Holy Grail War and has to summon a female "Servant" known as Saber for protection, a series of battles among sorcerers to fight for the possession of a relic that will grant one's wishes ensues. There are altogether seven "Masters" who can summon Servants and each compete to win the Holy Grail War. But things take a turn when Shirou begins to awaken powers within himself and tries not to fall in love with Saber in Fate/Stay Night!