After My Rebirth, I Escaped My Marriage - Chapter 23

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?

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

Finally caught up with the trend of crossing. Wait, everyone else has a golden finger when they cross, how can I become a little beggar after crossing!

Fortunately, the memory is still there, watching how I transformed from a little beggar to a top rich man!

- Description from novelbuddy

Everyone has a system they just need to meet hidden conditions to unlock it. A blacksmith system may unlock after a human walks by a forge. A master mage may unlock a system after attempting to control the mana in their body. Even something as simple as kicking a rock at a bucket can unlock the marksman system a unique system allowing for perfect accuracy. But what happens when someone reaches the age of fifteen and hasn’t unlocked their system? Walker is about to find out, time is ticking and he doesn’t want to live out his life as an ordinary human; he has dreams you know!