MTL - Warhammer Inquisitor - Chapter 2 Imperial Frontiers:

After seeking pleasure in the nightclub and a night of romance, he discovered there’s a seed in his stomach;

Shion, the ‘Hero of Darkness’. He was said to be the strongest hero ever. He believed one thing, and that was his current party members.

“I’ll defeat the Demon Lord with this party!”

That is what he swore to do, but a tragedy occurs. He was painfully betrayed by the girls that he trusted.

He barely held onto his life, but the incident left a deep scar in his heart.

He gave up on living, and while he was wandering around in a forest, looking for a way to die, a single monster appeared in front of him.

“Will you kill me, please?”

The monster asked Shion, who was still strong, despite losing his powers.

What Shion, who wanted to die as well, did was―

He became a teacher at the best magic academy in the empire.
….For being mistaken for someone else.

Qin Tian accidentally transmigrated into a sickly body, a body with broken Dantian that was unable to practice Qigong, in another world. Fortunately, God had mercy on him by giving him a level up system. Useless? That was him in the past. Not worrying about practicing Qigong, he was now able to kill Monsters to level up. Easy! Level up when killing Monsters; level up when killing people. An unbeatable sovereign of the clan in the eyes of other people, but in his eyes, he is a glittering big BOSS.

With this level up system, he will no longer encounter any bottlenecks during a breakthrough in cultivation like other geniuses; all he needs to do was kill as many monsters, clan heads, sovereigns, world experts … to have a better life.

Dedicating his life on a road to become an expert.

- Description from Novelupdates