The Princess Who Came to Kill

Princess Serena of fallen Sereland, disguised, infiltrates Prince Victor's manor for revenge, believing he destroyed her kingdom. She finds clues, and Victor, knowing her, protects her. The true villain is Emperor Damian, who practices forbidden arts and framed Victor. At the coronation, Serena exposes Damian and fights him with Victor, killing the demon. After war, they rule separately; Victor settles his realm and joins Serena forever.