Reborn: Super God of War - Chapter 11 - Expert-level Dungeon

After centuries of ruling the underworld with terrifying power, Lilith dies in an epic battle, only to be reborn in the human world. But instead of a grand rebirth as a queen of darkness, she's reincarnated as something far more mundane—a secretary. Rather than despair, Lilith finds this new life amusing. After all, who would suspect the devil herself to be working a 9-to-5?Settling into her new reality, Lilith embraces her role, living in a luxurious apartment and working diligently in her office. Though her devilish instincts are hard to suppress, she's determined to be the perfect secretary. But when people push her too far, the devil within still comes out to play.When a creep in the office dares to look at her the wrong way, she calmly fixes her gaze on him. “You keep staring like that, and I'll show you what a broken wrist feels like.” The man quickly scurries away, leaving Lilith with a satisfied smirk.Even the rich, entitled girl from accounting isn't safe from her wrath. “You think you can push me around just because you've got money? I've burned entire kingdoms for less. Don't test me.” She says this with a calm smile, her eyes glinting dangerously.The day continued like that—stopping creeps in their tracks, putting rude heiresses in their place, and being the flawless secretary she intended to be. But, of course, her boss—the CEO—had his eyes on her, more curious than ever. And while the entire office might fear her or wonder about her, she remained blissfully indifferent. This was fun. And she wasn't here to impress anyone but herself.Who knew being a secretary could be so... interesting?

As soon as he crossed over, Su Mu came to another world.

In this world, there are warriors, qi refiners, and all kinds of terrifying ghosts and monsters!

A good rebirth simulator turned into a death simulator because it was too dangerous.

For him, death is not the end, but the beginning.

In the simulation again and again, thousands of demons have been derived!

The flesh and blood are put into the pot, divided and eaten, turning into a bloody skeleton.

He died in a wrongful battle, his body did not rot, and he turned into a dry zombie.

Introduce thunder into the body, turn extreme yin into yang, and transform into a fierce reggae.

Devouring demon souls, suffocating the sky, turning into an undead ghost car.

Some people become immortals.

There are also people who die into demons!

- Description from novelbuddy

A young man with an extraordinary mind is off on an exciting adventure when he mysteriously wakes up in the body of a feeble slave-guy in a different, rich in quirks world.

The main character, a selfish jerk, would use extreme means to achieve his goals. However, he never allows his base instincts to overrule his sense of decency. He always pays back both good and bad deeds.

Will his (terrible/excellent) mentality help him make a fresh start? Will he get through misfortunes and hardships of the new world?

One day, Luo Jian woke up from his sleep and found himself in a locked chamber where the door and window were all sealed. A note with a few lines written on it was tacked to the wall: “Escape from this room within an hour, otherwise, you will die.”

There is a sequel called Reincarnation Night (轮回之夜) that takes place in the same universe but has different main characters

- Description from Novelupdates