Fate/Zero (2011)

S1E5 A Wicked Beast's Roar

As the clash between Lancer and Saber intensifies, Rider unexpectedly materializes, leaving Saber unsettled. Unfazed, Rider addresses the numerous onlookers hidden in the shadows, hinting at their presence. However, it soon becomes clear that he isn’t the only heroic spirit attracted by the fierce confrontation.