Rakuin no Monshou - Volume 1, Chapter 2: Two Boys

Working in a big factory for several years, Wang An, who was prematurely aging, accidentally obtained a cheat that can earn experience. The improvement of his skills brought him unexpected surprises.

It turns out that some things are not just legends.

Lightness kung fu can really make people walk on the snow without a trace, and fly over the walls.

Vajra is not broken, it can indeed produce the power of vajra, and become the body of vajra, invulnerable to swords and guns.

Congenital qi, grasping iron into mud

 …

Brushing experience does not rely on simple repetition, but requires continuous learning, summarization, and comprehension.

- Description from novelbuddy

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!

- Description from Novelupdates

Lucia grew up not knowing she was a princess.

He always told me that he dreamed of me at night.