A Mistaken Marriage Match: Record of Washed Grievances - Chapter 84

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

This is a story about a badass,

In the original lines of the novel, I was a villainess—used as a political tool by my father and older brother—who ended up dying at the hands of my future husband.

When Arran decides to become a mage, he quickly discovers that magic can be more dangerous than he had ever imagined. Soon, he finds himself hunted for powers he never knew he had.