The world is ending. Monsters from legends appear everywhere. They eat people, conquer the streets, and begin to make dungeons in the buildings and subways. If you could choose one job in this decrepit world, what would you choose? For a “necromancer” extinction is my playground and death is my wealth.

Gu Yangchun, who betrayed the Orthodox sects, became a demonic human under the Heavenly Demon.

Living as a demonic human, he led a life filled with regret. He committed countless evils not of his own accord, but under the orders of the Heavenly Demon.

In the Great Orthodox-Demon War, thanks to Wi Seol-ah, who cut down the Heavenly Demon that made even the three supremes of the Orthodox forces kneel, Gu Yangchun was taken prisoner by the Orthodox forces and suffered for his sins.

With whatever morals he had left in him, he died giving Wi Seol-ah information about the Demon Cult due to a bind the Heavenly Demon had placed on him.

Then, for some reason, Gu Yangchun regressed to when he had first met Wi Seol-ah. Realizing the regression was not a dream, Gu Yangchun decided to live a quiet life. However, bad ties from his previous life began to draw near, one by one.

Killed on the battlefield without glory to his name, Yuseong Dan receives an opportunity to grow stronger with a strange quest and level system. But each quest he’s forced to fight only seems to be getting harder and harder. Can he level up enough to avoid the same miserable ending and become the powerful hero he wishes to be?

The descendants of mankind, born in the labyrinth and raised on the milk of monsters, possessed special strength and strong bodies. When they returned to earth, mankind referred to them as dungeon babies. Among them, Kim Jinwoo was born in the deepest labyrinth.
“I never tried to become strong, I just wanted to live.”
From the lowliest excavator to the king of the labyrinth, his life story is now unfolding.

There once was a hero who was deemed the strongest on Earth.

“But he died. How would someone that we killed return?”
“Yeah. I’d love to see him try and come back.”

However, 20 years later, he actually returned!

“Why are you guys so shocked? Did you do something that you feel guilty about?”

‘These motherfuckers. I’m not going to let them be.’

From MangaHelpers:
29-year-old programmer Suzuki Ichirou finds himself transported into a fantasy RPG. Within the game, he's a 15-year-old named Satou. At first he thinks he's dreaming, but his experiences seem very real. Due to his use of a 3-time-use special power (meteor shower), he ends up wiping out an army of lizardmen and becoming very high level. He hides his level and plans to live peacefully and meet new people, though developments in the game story (like the return of a demon king) might get in his way.

When Kirishima Ran and his classmates were transported to another world they each received an ability. However, the ability he received, [Sexual Lunatic], has caused nothing but trouble for him. His ability allows him to make any girl he comes in contact with his slave. Because of his ability, his classmates have shunned him and forced him to separate from them. With the fires of revenge burning inside his heart, Kirishima decides to overtake the class from the shadows. One by one he turns his classmates into slaves and fill his desires.

All the members of my sect are abnormally strong. All my disciples turn out to be big shots, and I'll definitely become invincible in this world!

After being held in disdain and having his life put in danger, an orphan from the Demonic Cult, Cheon Yeo-Woon, has an unexpected visit from his descendant from the future who inserts a nano machine into Cheon Yeo-Woon's body, which drastically changes Cheon Yeo-Woon's life after its activation. The story of Cheon Yeo-Woon's journey of bypassing the Demonic Cult and rising to become the best martial artist has just begun.

Devoid of professional skills, unemployed Yu Damduk was forced to take a part-time job. Frustrated with his pathetic life, he vents to the gods, gets stricken by lightning and passes out.
[Hiring] God is waiting for you.
When he wakes up, he finds a status window floating before his eyes.
Since I have nothing to lose anyway, let’s go with the flow…
Jumping into God’s Part-time world to have a better life, the adventure of Yu Damduk, who became the lowest-class God in the part-time world, begins!

In the mobile gacha game infamous for its atrocious difficulty, the Master ranked 5th in the world, 'Loki', loses consciousness while raiding the Dungeon.

'What? I'm a game character now?'

After waking up, 'Loki' realizes he has turned into a Level 1, 1-Star Hero—'Han Yslat'. To return to Earth, he must lead the newbie Master and heroes and clear the 100th floor of the Dungeon!

'You messed with the wrong guy.'

This is the story of hard carrying by Master Loki who never accepts even a single defeat.

Akira Kamishiro was a very successful manga author, who was diagnosed with blood cancer one day. He regretted the way he lived, where he could only build up empty relationships. Angry at his mother for asking him to send her some money, he died in a car accident. He was given a chance to choose his new mother and reincarnate in another world.
Akira, not wanting to have a repeat of his past life, decided to choose an ordinary but safe life.. He was reincarnated as Akira, the only son of a magic store, with his previous life's memories. He had no talent for swordsmanship or magic, but he didn’t care as he was still loved by his family. At one point, he realized that he can embody various things by "drawing a picture". That's when he noticed his cheat ability...!?
This is a story of Akira who wanted to live a mediocre life in another world and his adventures to protect his peaceful place!!

The Earth’s existence is under threat once more as Itarim, the gods of other universes, seek to fill the void left by the Absolute Being. Sung Jinwoo has no choice but to send Beru, the shadow ant king, to awaken his son’s powers and start him on the journey he once took. Suho must conquer the shadow dungeon and earn his place in the world of hunters as he navigates through a new world against a new evil looking to swallow the world whole.

Kim Jun-Woo, the world’s first SSS rank genius hunter.
He is an incredible user of ability, but his horrible personality leads to problems with his reputation.
In the midst of his troubles, he was attacked and killed by an unidentified group.
And when he opened his eyes, he had returned to the past of 10 years ago.

Though he tries to become a hunter again and raise his rank, his skills were all sealed by the karma of his previous life.
In order for that to be released, he needs to work as a ‘Dungeon Cleaner’, which is infamous for being extremely tough in this industry?!

But this cleaner, he’s different!
Not only monsters—troublesome hunters, superiors only taking up positions after they’re hired out of nepotism, and even people who will be colleagues with him.
He’s making a complete mess to clean everything up.
The ex-hunter, who is stronger than the current hunters, and his crazy cleaning begins!

In a brutal, lawless medieval world where war and poverty reign, and twisted magic defies all reason, the captain of the guards grinds through another grueling day, pushing his battered body to the limit in a land where survival itself is a merciless test.

The golden age has dawned for treasure hunters, who raid treasure vaults all over the world in search of glory, despite the dangers.
Immeasurable wealth, fame, and power await those who prevail.

"Let's be treasure hunters!"
This promise between Krai Andrey and his friends came to a sad conclusion when young Krai realized he didn't have a treasure-hunting bone in his body.
Yet for some reason, people's expectations of Krai continued to grow—as did the danger to his life.
While his friends became greater, greedier beasts, Krai mastered the art of begging and pleading!

Witness the weal and woe of a man who just wants to retire.

After the gods dropped her in the world of her favorite fantasy romance novel, Lithera was quick to realize that happily-ever-afters were never easy to get. Given another shot at happiness, she is now determined to avoid the mistakes of her previous life, starting by meeting the sweet and caring Grand Duke she spent years exchanging letters with… Another typical female lead, with another typical Duke, promised to wed. Will this story go the typical path we all expect?

If you max out your level in-game, you can get heaven-defying powers in real life?!

Player Ling Ce finally obtained this reward through his hard work but ended up receiving the most useless skills. Just as he was mourning his luck, a mysterious power brought him back to three years in the past. With the experiences and memories of his previous life, how many different wonderful things can he bring to his new life?

Sacheondanga was a famous family of poison and memorization, but has now fallen.
Yeon Myeong, who was born there, suddenly became crazy about the sword.
I awaken to my past life where I reached the state of swordsmanship.

'I want to live a normal life this time.'

If I wanted to live a normal life, I would have to hide my swordsmanship skills.
But there are too many things that get in the way.

After he and his entire class die on a field trip, Odamori accepts an offer from a mysterious man to be reincarnated. However his new job turns out to be that of a 'Slavemancer' with the power to dominate the minds of others and turn them into his toys, which he happily takes on. Soon however his evil actions lead to a Princess Knight (who turns out to be one of his previous, more popular classmates) being dispatched to apprehend him. But Odamori of course has something different planned for their reunion.