Fate/kaleid liner Prisma Illya - Season 3 Episode 9 Golden Boy

As Caren experiences backflash from her observation spell, the boy, revealed to be the Heroic Spirit of the eighth card, reveals that Miyu is a princess from a parallel world who was born as a complete version of the Holy Grail. Feeling she can't escape her fate, Miyu gives Sapphire to Illya before being pulled into the vortex, completing the Heroic Spirit's ultimate form. Learning that Miyu is still alive inside the demon's body, Kuro and Bazett hold off the demon while Illya, gathering her resolve to rescue her friend, combines Ruby and Sapphire's power to unleash a powerful new transformation.