I Slay Gods and Demons in the Deceit Night - Chapter 19 - 17: One Man Holds the Fort, Darkness Brings Wu Chang

Cheng Yin likes her deskmate Chen Yan for a long time, but she never dared to confess her love for him, and the phrase ‘I like you’ is a secret hidden in her heart, but she can’t help but blurt it out from time to time…
Cheng Yin: “Chen Yan, I’ll whisper something to you.”
Chen Yan always leans over quite cooperatively, “What?”
The words came to her lips, Cheng Yin blushed and changed it into: “Your pants are unzipped.”
Chen Yan: “?”
Later, this kind of useless whispering has become more frequent, and Chen Yan listened again without moving a bit: ” Speak.”
The day of the party, Cheng Yin drink for the first time, Chen Yan became two in front of her eyes, she grabbed the person with both hands, want to try to catch the real Chen Yan, only to have her hand caught, he lowered his head in her ear and said: ” Let me whisper to you.”
Cheng Yin: “…… what?”
Such bad behavior, she thought it was something bad, Cheng Yin checked her pants and made sure the zipper was closed before she lean over.
The man’s breath blew softly in her ear, laced with a bit of the smell of wine.
“I like you.”

- Description from Novelupdates

The tens of thousands of universes have merged. The disintegration of spiritual force led to the momentous collapse of the great Cultivation World, a mighty era that had endured through millions of years of history. In the wake of the large-scale invasion of the Wilderness, the Avalon of Five Elements has become the practitioners’ last stand.

Qin Chen crossed into Taiyi Holy Land as a sweeper, and at the age of sixteen awakened the system. As long as he signed in at different places, he could get different rewards.

Sign in at the Land of Emperor Ruins and get the world’s No. 1 Chaos Holy Body and the Chaos Emperor Sutra!

Sign in to seal the magic land and get the quasi-emperor soldiers!

Sign in at the Refining Hall and get the God-level Refining Technique!

Sign in at the medicine garden and get the medicine of immortality!

Sign in at the Imperial Palace and get the Emperor-level forbidden magical power ‘Resurrection from the Dead’!

…

Qin Chen thought that he would just sign in silently until the world was invincible.

One day, the relics of the Great Emperor will appear in the Holy Land, all the holy places, families, and ancient dynasties have come, and there will be an unparalleled demon king in the relics, killing countless powerhouses, ruling the world, and wanting to destroy the Holy Land.

In desperation, Qin Chen could only walk out, slapped the Demon King to death, and sighed: “I just want to be a sweeper and sign in silently. Why do you force me to take action?”

- Description from novelbuddy

This is an alternate history. Decades after the fall of the Eastern Jin Dynasty, the world is still in chaos, although there is hope for reunification.