Debstam is a habitable planet where Mongul maintained a home here, from which he would launch his attacks upon the heroes of the universe and to which he would, in time, return. He shared this dwelling with his two children, Mongul the Younger and Mongal. However, he was absent for long periods of time, leaving both children alone. The planet may be totally unknown, since Mongul once killed a group of stranded aliens rather than keep them alive.
After Mongul's death, his children continued to use it as a base (if not necessarily a home).
Towards the end of the Sinestro Corps War, Green Lantern Corps members Stel and the Green Man chased a renegade Sinestro Corps member across the Cygnus star system. His ship was heavily damaged and he crash landed on Debstam IV. Crippled and dying, the Corps member sought out a suitable replacement - one who could inspire great fear. What he found was the tyrant Mongul the Younger. Mongul snapped the Corps member's neck and took his Qwardian Power Ring.