Douluo Dalu 2: The True God King - Chapter 148: [DD2]:

On a normal boring day, a message appears, inviting him to a Tutorial.

Known as the youngest academician-level senior engineer, Zhao Guoyang was reborn in the 1990s. In this era of economic globalization, with his extraordinary wisdom and extraordinary insights, he created one miracle after another and became a name that shocked the world!

Wisdom is condensed every bit, brilliance is created by sweat, and witness the rise of a great power!

- Description from novelbuddy

After losing his parents to an accident, Haruto is thrust into a state of depression. Realizing he never had the power to change things, he eventually took his own life. Before moving on, he’s selected by beings greater than his understanding to balance out a world suddenly facing peril. The world of Mordell, where demon-like creatures and beasts roam, and Guilds of ability users called Warlords are the force to combat these creatures. Armed with the power to change things, he has the choice. Continue living in despair or accept his second chance and become a true Warlord.

To pass as an imperial concubine, one must be professional.

Actually, the profession of an imperial concubine is pretty good. The emperor will accompany you in eating and drinking, and even pay you for it. What’s not good about that?