Li Yi was only grinding his level at the Foreignland Entrance and Demonic Forest. He was far away from the real Foreignland.
Everyone was still fighting hard at Sin City under Fluttering Snow Purple Water Chestnut's leadership. However, it was practically impossible for them to kill the Fourth Demon God and Fifth Demon God any time soon.
The Fourth Demon God and the Fifth Demon God were known as the Twin Demon Gods. Since they always moved out together, they had no choice but to kill them simultaneously.
It would be a dream to win against two Demon Gods simultaneously if the average players' level was below Level 160.
The level difference was simply too wide apart.
Players were better off killing monsters to gain high EXP than befriending demons and leveling up via quests in Sin City. This was the reason why Li Yi chose to level up by killing monsters.