The planet Vega is a planet in the Vega star system. It was colonized by the Citadellians, the race who founded the major space faring empire known as the Citadel. It has many moons, one of them is called the Moon of Games. There are also several orbiting cities, and it is considered the playground of the Intergalactic Underworld.
This world was originally a cold, barren world in a state of perpetual winter. Although the closest planet to Vega, it is protected from the blistering heat of the star by a thick layer of dust-like matter that absorbs energy and light, shielding the planet's surface. The First Citadellian chose this world because of its lack of natives and its harsh environment. This forces the Citadellians to adapt and survive or die.
Eventually the climate of the planet was changed to more favorable conditions, and many other races from across the galaxy began to come there. The Intergalactic Underworld used at least some of it as a recreational planet, where various criminals from throughout the galaxy that are members of the Intergalactic Underworld, could come to play games.