The Assassin's Enemy Lover - Chapter 612 - NSFW

The protagonist travels through Shu Mountain and becomes a demonic dragon guarding the heavenly book in Dinghu Peak.

A supreme expert in the Immortal World had died, and a strand of his soul returned to its original body on Earth. Tang Xiu discovered with amazement that ten thousand years passed in the Immortal World, yet only a single year passed on Earth.

Ruthlessly betrayed by his lover and trusted friends, Tang Xiu found that his soul went back to his previous body on Earth, and, despite he spent 10,000 years in the Immortal World, just a year has passed on Earth and many things have changed. Having an unsurpassed knowledge, Tang Xiu will protect his loved ones and go back to the Immortal World to take his revenge.

- Description from Novelupdates

A hero must be compassionate, selfless and courageous.But that isn't all. Because a hero must also be powerful.In this world, power is everything. Strength decides who gets to save lives and who's left with community service. That’s why I was nothing — a rank 50 E-Class reject, skating through the streets, saving what little I could while the real heroes battled gods and monsters.Then one day, I died. Almost.Dragged into the abyss, I was given a second chance: the Forever Core. An armor that evolves. A system that never stops adapting. Every battle, every hit, every mistake, I come back stronger.Now, the monsters that once crushed me can’t kill me the same way twice.I must adapt. Evolve. I must grow stronger and fight harder. Because humanity is worth fighting for.Even if I have to burn every villain alive to prove it.

Dynasties rise and dynasties fall, like the tide washing the sand.