How Did the Undercover Demon Realm Become the Goblin God?

The mage Yue Heng was ordered by the Sword Saint to go undercover in the Demon Realm. There are bloodthirsty werewolves here, there are succubi who like to dress up as women, and there are soft and fragrant tree demons. Yue Heng has never forgotten his mission, to collect intelligence for the human race... But it wasn't until a mission that he truly realized that the Sword Saints and others were more terrifying than the demons... In a desperate mood, Yue Heng thought of the goblin boys who were undercover in the Demon Realm. In the end, he gave up the past and became the Goblin God, leading the Goblins to kill across the planes. [Darkness, inhumanity, decisive killing]