Start in DxD as Motohama: Leveling Up in Another World - Chapter 13: Unusual Situation (I)

The most feared Assassin in the world died because of vengeance.

Omnipotent A-Grade Cool Female Lead VS Secret Passionate and Domineering Male Lead That Loves Assuming and is Easily Jealous

Meet Gu Yu—a college dropout and a talented incense maker, and at the same time, the rather stoic protagonist of this story. Despite his somewhat introverted manner, he has a tendency to make sarcastic remarks in his thoughts. One day, after saving a squirrel, a windfall (metaphorically and literally) dropped into his lap. Stumbling into the cultivation world with little help, he was not turned into Superman overnight (as he would like). Apparently, becoming a cultivator would not make your life easier, at least in the beginning.

Somewhere along the road, he ran into Jiang Xiaozhai, a young woman who’s got the brains, the beauty, and maybe one or two secrets of her own. As it turned out, the two made a perfect team—Mulder-and-Scully style. Motivated by many unanswered questions, they had been running up and down the country, getting into all kinds of trouble, and learning more of the modern cultivation world, which is by no means the same as in the ages long past…

- Description from Novelupdates