Leopold Mercé, born Fausto Fidel Melze, carries noble status as the son of royal-blooded figure Leopold Melze. This lineage fuels his consistently cocky and self-assured demeanor, especially evident in his interactions at the flight academy. He cultivates a fierce rivalry with Kal-el Albus, primarily centered on competing to become Claire Cruz's flying partner—a conflict reflecting his pride and sense of entitlement. When the flying island of Isla faces an existential crisis from the Sky Clan's vast air fleet, Leopold sets aside personal animosity. He mobilizes alongside Kal-el and fellow pilots in a coordinated defense of their home. His narrative concludes during a pivotal battle in episode 8. While engaging Sky Clan fighters to cover the retreat of his flight class survivors, his aircraft is intercepted and destroyed, resulting in his death alongside his pilot. This sacrifice demonstrates his commitment to collective survival over individual ambition or status.