Kuro no Maou - Chapter 442

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

Mason was a mercenary, until the day he died on a mission after being betrayed by his unit.

This is just a simple, sweet romantic moments.From A Silent Voice, I Want to Eat Your Pancreas, Your Name, Saekano: How to Raise a Boring Girlfriend, My Teen Romantic Comedy SNAFU, Durarara, and etc