Death March kara Hajimaru Isekai Kyusoukyoku (WN) - Book 2 - 2-1. Disaster Relief and the Shrine Maiden

This world is not only as the public knows it; there is an underworld that ordinary people don't encounter.Government agents handle troubles in the shadows, while corporate assassins privately deal with issues.Assassins, mercenaries, arms dealers, and spies exist, along with a dark web that ties this world together, and tycoons who attempt to control everything with money.Gao Yi entered the underworld, unbeatable in close combat, carving out his own domain.But there are guns in this world. Beyond seven steps (close combats), guns are faster.Within seven steps, guns are both accurate and quick.Only within three steps does Gao Yi's punch become faster.Unable to beat them, he chose to join them, aiming to rule them all.To rule everything, become the king of killers in the eyes of mercenaries, the king of spies in the eyes of assassins, the king of killers in the eyes of spies, and the king of intelligence in the eyes of arms dealers.Until he is crowned king by the entire underworld, Gao Yi is the ultimate firepower.

What would you do if you were reborn in the world of Battle Through the Heavens without a distinguished background or an elder in your ring and just a decent talent?Luckily, Xiao Ming has awakened the Life Simulator System![The Life Simulator is on]......[You have experienced an ordinary life.][Elements are being chosen.][Currently available: Green Lotus Core Flame, Flame Mantra, Woeful Poison Body.][Please choose one.]Every seven days, he can choose to extract one of the elements from his life simulation.In this way, Xiao Ming began his ordinary life.

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

A college student was returning home after studying abroad for several years when the end of the world happened. A dragon appeared out of nowhere and attacked the plane he was in, thanks to an incredible amount of luck and his quick-thinking, he managed to survive the plane crash only to get stuck on a tropical island. A weird system took over the world and brought monsters to Earth. While nations collapsed and the world as a whole was being destroyed by ridiculous monsters, Leon was stuck on a godforsaken island with no chances of being rescued. What will happen to him? How will the world change while he is away? Will he even manage to return? The story, all names, characters, and incidents portrayed in this production are fictitious. No identification with actual persons (living or deceased), places, buildings, and products is intended or should be inferred.