The Game Master is a character in He-Man and the Masters of the Universe.
The Game Master is a spacefaring villain who is fascinated by games and gladiatorial combat. He travels the universe in his Cosmic Arena with a motley crew of various creatures he describes as the most powerful warriors in the universe - beings from many worlds that he captured and enslaved. Obsessed with always winning, he has armed himself with an impressive array of weapons and technology designed to ensure that he always has an unfair advantage in every conflict.
When the Game Master met He-Man, he was impressed by his strength and became determined to make him participate in battles in his gladiatorial arena. When he declined, the Game Master sent a winged spy after him, who determined that He-Man was close to Teela after eavesdropping on one of their conversations. The Game Master and some of his creatures attacked the Royal Palace, kidnapped Teela, took the Power Sword from Prince Adam as a trophy, and told him to send He-Man to the Cosmic Arena if he ever wanted to see his friend again.
With some help from Orko and Cringer, Adam managed to infiltrate the Cosmic Arena and tried to break Teela free. However, he and Cringer soon found themselves in a gladiatorial match against Kraggox, the Game Master's best warrior, who knocked Teela unconscious when she intervened. Orko distracted the Game Master and his minions while Adam recovered his sword and turned into He-Man, who was able to defeat Kraggox with ease. The Game Master then confronted him personally, using his trident and an exploding discus even after He-Man challenged him to unarmed combat. The Game Master ordered his creatures to fight He-Man, and was unwilling to accept his loss as they deserted him. He was taken to the palace jail, and the creatures he captured were allowed to return to their homeworlds.