Previously, I had planned to return to the Pangu Realm with the little monkey and Hei Kui in tow. However, Hei Kui later decided to stay in the Netherworld World temporarily. When Sun Wukong asked him why, Hei Kui was initially reluctant to say. It wasn't until later, after he'd had too much to drink, that he revealed his reason when Sun Wukong asked again. In Hei Kui's own words: "I'm not going back with you. I plan to take some time to fully consolidate my cultivation, then join the Flame God in seeking revenge. Heh, if you're a brother, don't try to stop me."