Fate/Zero

Synopsis

Caster and Uryuu returns to their lair and are dismayed to see their "artwork" destroyed by Rider's fire. Uryuu cheers Caster up by sharing his twisted view that God, who Caster hates the most for Jeanne's death, is just a spectator who enjoys seeing humans do whatever they want. Impressed by his Master's idea, Caster plans a "grand spectacle" for God. Meanwhile, Waver has second thoughts about being a worthy master for Rider, but Rider encourages him to believe in himself. Suddenly, Waver, Rider, Saber and Iri sense magic from Mion River. When they arrive, they witness Caster summoning a giant demonic monster. Rider informs the other contestants and they all agree on a temporary alliance to stop Caster before his monster destroys the city. With Rider leading the vanguard, Saber joins him to give Lancer an opening to use his spears on Caster. (Source: Wikipedia)