At some point, Dulok was chosen by the Guardians of the Universe to become a Green Lantern of his world.
When Iolande was crowned as queen of Betrassus, she had to chose a king and the greatest warrior on Betrassus, Kothak claimed her hand. However Dulok found him an untrustworthy fellow and decided to battle against Kothak for the title of king.
At the time of his announcement Hal and Kilowog visited the planet, he explained to Hal that he would leave the planet and aid him against the Red Lanterns and leave the planet in the hands of Iolande. However he was poisoned and killed by Ragnar who desperately wanted his ring, but chose Iolande instead of him, and he hid his body.
- 105. "Heir Apparent"