My Celestial Ascension - Chapter 614: Miss Zara Couldn’t Sleep (R18)

“For those who dare call themselves gods, I, Wen Ran, will crush their legacy beneath my feet. Even dogs are more honorable than those filthy bastards!”A feared Godslayer, who, due to betrayal, perished under the might of the heavens, having his world destroyed. Saved by a mysterious system, Wen Ran was granted a second chance at life but reincarnated in the body of a lowly slave. Hunted by the gods who sought his head, Wen Ran vowed to reclaim his title by showing heaven his vengeance as a 'God Slayer.'

An ordinary (?) grandfather, Choi Chuntaek. In an effort to protect his granddaughter, he started the virtual reality game 'Arkstar.'

Then... he accidentally obtained a legendary class?

Fate had never been kind to Ji Ning. Wracked by illnesses and infirm his entire life on Earth, Ji Ning knew early on that he would die as a teenager. What he didn’t know was that there really was such a thing as life after death and that the multiverse was a far larger place than he thought.

A good-for-nothing man married a beautiful girl but was kicked off the bed on the wedding night. Furiously, he wrote a bill of divorce and ran away.
He was schemed a car accident in which he nearly lost his life. However, it turned out to be a blessing. He swallowed the soul that passed through the outer world, thus obtained superb medical skills and martial arts.
Later on, with the silver needles and invincible martial arts, he embarked on the road of counterattacks and was committed to his great dreams.

- Description from Novelupdates