Inside the Cave of Obscenity - Vol 9 Chapter 7: Hero and Slime

《The Peter Pan who doesn’t want to grow up, Wang Chao & the Poor and Handsome Cinderella, Xie Zhuxing》

Two plain Jacks, one annoying and one scheming. An idiotic story that might not be sweet.

- Description from Novelupdates

A decade ago, the first dungeon gates appeared, but some vanished before they were ever conquered. The MC, a low-rank hunter, awakens the Lost Gate System, granting him access to these forgotten dungeons where legendary monsters and artifacts are trapped. Each completed lost gate grants him absurd power, but also reveals terrifying truths—these dungeons are prisons for ancient beings who want revenge.

The unparalleled Demon King Ye Xuan, who was able to heal the death or the living alike and holder of the medicine Holy Scripture, was betrayed and killed by his fellow Demon Kings. But he reincarnated into the body of Ye Xuan, the prodigal son of the Ye family and vowed to himself that he would return to his peak and take back everything that belonged to him!

- Description from Novelupdates