The Hero Returns - Chapter 71

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 didn’t know this was a world inside a game. And I didn’t know my master was a mid-boss. “No way… wasn’t she supposed to self-destruct because of her personality?!” …I’m sorry.

Village woman Su Xiumei, “Fei, sister is ill, come help sister with a treatment!”Lin Fei gave a wicked smile, “Xiu Mei sister, don't lock your door tonight, I'll come give you a shot and you'll be fine!”Su Xiumei, “You little rascal, you're really naughty!”