Reincarnated With A Glitched System: Why Is My MP Not Running Out? - Chapter 641 The Secret Power Of The Darkage Lineage

Ian Percus, the second son of a countryside Viscountcy.

One day, he received a love letter from the future.

‘If we don’t protect the future, the world will perish.’

With an ominous warning scribbled by someone

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

As a fiery young shrew, Xu Weilai was confident that no one would be able to resist her charms. However, time and again, she was thwarted by Gu Yu.

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.