The King Of Heroes is a unique 6-star unit in the game, based on Gilgamesh from Fate/Hollow Ataraxia and Fate/Grand Order: Absolute Demonic Front Babylonia. He can be obtained via Banner Z of the Hero Summon or by evolving Gate. The game permits only one King Of Heroes per player, and he cannot be sold. This rule likely exists to maintain game balance, given the King Of Heroes' power and versatility in attack styles.