The Gladiator is the informal name given to Myzax, a terryifying and undefeated gladiator in the Galra prisoner fighting ring. Shiro was forced to fight him in his imprisonment with the Galra. It used to be a monster, with only a staff with an orb as a weapon, but Haggar decided to increase his strength with quintessance, in order to make him a threat to Voltron. This turned him into a Robeast.