Illyasviel von Einzbern

An aristocratic mage from the Einzbern lineage, this powerful young girl arrives in Fuyuki to compete in the Holy Grail War. Though she possesses immense magical talent and commands the legendary hero Berserker, her haughty demeanor masks a complex bond with Shirou Emiya, whom she calls "Big Brother." While her destiny involves tragic struggles as the daughter of Kiritsugu Emiya, alternative timelines see her navigating life as a magical girl alongside Rin Toosaka.