The Thunder Beast Pirates are a group of pirates that originated in Paradise. They are the crew of the story One Tomorrow, and are led by the story's main protagonist, Hiro Xanthe. The "Thunder Beasts" obtained their name from their Captain's epithet, "Thunder Beast Hiro", which Hiro first gained when he defeated the Marine Captain, Seizon with his Thunder Beast Hammer technique. Following the events of The Phoenix War, the Thunder Beasts were disbanded in order to get stronger under Hiro's orders as he knew that at their current state, they could not survive in the New World.