Twinrova is the pair of witch sisters, Kotake and Koume from The Legend of Zelda: Ocarina of Time. They serve as the boss fight of the Spirit Temple.
I really loved using the Mirror Shield in this battle. Just so fun to see the ice beam or fire beam shoot back at it's caster's counterpart.
Then they fuse into the true form of Twinrova. Giving you double the trouble. It's a nice battle.
They somehow open a shop in Majora's Mask despite dying in Ocarina of Time. Talk about outstanding work ethic!