Thace is a member of the Blade of Marmora in Voltron: Legendary Defender.
When Thace infiltrated to Zarkon's Empire, he worked for a while with Galra Commander named Prorok. But later he sent secret messages. But later Galra Druids learned that he was the enemy spy and he was captured and interrogated, but later he was released. And when he met with Keith from Team Voltron they tried to circumvent the Galra's exchanged codes, and he was going to overload the system main power. Keith got away but Thace remained after the sacrifice of himself, and he managed to subvert the system.