Princess Celestia Heroic Battle/russgamemaster

Required hero: Princess Celestia

Enemy: Nightmare Moon

Opening dialogue
Luna: There can only be one Princess in Equestria. ME!

Celestia: Luna, NO!

Luna: Luna? I'm Nightmare Moon! (she transforms and starts the fight)

Special condition
Celestia passive: Luna, NO! - Celestia is hesitating to hurt her little sister, so your attack and accuracy are greatly reduced.

Nightmare Moon passive: Flammable - any fire or energy attack will trigger an explosion on her, causing extra damage and Burning.

Empowered Iso-8
Fiery Iso-8 - Nova Strike exploits combos and causes Pyrophoric. Protects anypony from fire attacks, not just allies under 50% health.