Slix Vigma traveled through the universe capturing aliens and used them to fight for the amusement of the galaxy. He teleported the aliens into his ship, where he forced them to fight each other in arenas by using electronic implants. These illegal fights used to be watched by huge audiences.
Ben 10
In Grudge Match, Slix Vigma controlled the Megacruiser and used it to attract the alien public to gladiator-like fights. He kidnapped both Kevin 11 and Ben to fight for him after he observed them fighting on Earth. Ben used Upgrade to overpower him, although it was a little hard to take control of him. When Ben timed out, Slix attempted to kill him for that, leading to Kevin 11 ultimately destroying him.
Omniverse
Slix Vigma returned in No Honor Among Bros as the announcer of the Golden Fist Tournament. His personality has become much more excitable, similar to a stereotypical sports announcer.