Mongul

Mongul is a powerful alien supervillain from DC comics, the ruler of War-World and one of Superman's greatest foes, though he has also been seen in other media outwith the Man Of Steel (for example a toned-down version of Mongul was seen in the cartoon series Batman: Brave and the Bold). Mongul is a vicious tyrant who often forces heroes and villains alike to fight for his amusement and is a shameless sadist, such contempt for innocent life has made him especially hated by Superman and Mongul is one of relatively few villains who have almost succeeded in pushing Superman into a murderous rage (others who did this were Darkseid and Lex Luthor). During Underworlds Unleashed, he was offered more power by the demon Neron. However, his pride refused him, and soon he was killed and his soul taken by Neron.

After Hal Jordan's return, he is seen alive and back on earth to punish the planet for his father's failure's. Despite being helped by his sister Mongal, he kills her after returning home.

Recently Mongul has also become a member of the Sinestro Corps, and took over a part of the Corps after Sinestro was imprisoned. He bested Arkillo and took over Korugar as the new homeworld. Confronted by Sinestro himself during the Blackest Night, he was bested and soon defeated by having his rings overriden and the Yellow Central Power Battery dropped on top of him. Sinestro stated that no one, yellow ring or not, can endanger the lives of the people of Korugar.