Itai no wa Iya nanode Bōgyo-Ryoku ni Kyokufuri Shitai to Omoimasu - Chapter 286

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

I really just want to lose money! T_T

Due to a mistake on his student’s part, a super Martial Artist had received a wrong class in an online game and had become a mage. He who was used to curbing violence with violence and using strength to subdue strength could only make the best out of his mistake. Taking on a new lease in life, he became a violent close combat mage. When strength and magic came perfectly together, a new gaming path had been opened by him!