MTL - Horror Web - v3 Chapter 97 3 people

Past life, her spirit root was dug out from her body. She had wholeheartedly dedicated herself to the just path, but she was sentenced as an evil demonic cultivator.

“In order to survive the future great war, we must take drastic measures. We need to summon warriors and train them before time runs out.”Thus, millions of earthlings were reincarnated in an alien, medieval world governed by swords and magic to save its prophesied doom.Among those individuals, one's situation inexplicably deviated from the others.Thrust into a rotting house in a ghostly body, Adam found himself bound to a wailing baby. With a heavily damaged soul and the snarky remarks of a system, he began his years-long quest to recover his body.Armed with his mind, he'll educate the baby and slowly watch him turn into a good youth. However, he would have to make a choice: suffer as a ghost until he finds an alternative that might not exist, or possess his body and reincarnate.He was far from imagining how dangerous this world full of possibilities could be, prompting him to question everything he knew... Including himself and this world's intentionally blurred history.

Freshman student Yang Dingtian possesses the Nine Yang Body, found only 1 in million. His Yang Fire is incomparably vigorous and thus, he cannot be near a female’s charms for his entire life. On the night of his 19th birthday, he decided to bid farewell to his virgin life. After stealing and tasting the forbidden fruit, he spontaneously combusted as the result!

In death he crossed over to another world; a world that held respect for Martial Power. His, originally, catastrophic Nine Yang Body was the Nine Yang Body that couldn’t be seen in a millennium! He was saved by a mysterious old man when he was at his last moments and the old man received him for a disciple, then betrothed his daughter to him. Thus, in this odd way, Yang Dingtian became the successor of the largest clan under Heaven, and became the number-one-beauty-under-heaven’s fiance.

- Description from Novelupdates

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?