A weak and sickly boy, Sung Woo-mun's condition worsens when he loses his mental capacities, owing to a painting gifted by a sage. He grows up as the 'village idiot', pitied by his own parents. But unbeknownst to everyone, his life is about to change soon, and a new destiny awaits him. When Sung Woo-mun turns 20, not only does he have an epiphany, but an undefeatable martial arts power begins to bloom inside the painting. What could all of this mean for Woo Mun? And what strange world awaits him?

High school student Mikoshiba Ryouma was summoned to a different world in the middle of a war. Sensing the malice from the one who summoned him (a summoner of the O'ltormea empire), he uses his martial arts to run away, killing important people of the empire during his escape. After the escape, he rescues two twin sisters from the hands of thieves. The sisters who can use magic, swear to serve him as subordinates. Thus, Ryouma begins his journey on the path of the supreme ruler.

Bi-Kwang is a handsome young warrior who becomes a drooling mess whenever he sees a pretty girl. Out on the road he meets an extraordinary swordfighter with no name who is searching for a legendary master warrior. Bi-Kwang promises to aid the swordfighter if he lets Bi-Kwang meet his beautiful sister. Of course, it turns out the swordfighter is the sister, Hwa-Rin Dahm, and she must switch identities to keep the plot moving along. Bi-Kwang is immediately smitten, and thus we have a triangle involving only two people.

This manhwa was made into a MMORPG.

“Yan,” the protagonist, was brainwashed by the emperor and lived as his puppet. After finding out he was being played by the emperor, he planned to seek revenge, but collapsed due to the emperor’s might. He thought he had died, but when he woke up, he realized he had regressed to the time when he was a recruit. Whether to seek revenge on the emperor or to find his family. The choice lay in his hands.

Ryu-Yeon lost his father to a disease when he was only 10 years old. With the skill he learned from his father, he could carve wood to create wonderfully intricate sculptures. One day, after completing making the sculptures of his parents, Ryu-Yeon was greeted by an elderly man who was impressed by his sculptures. The old man saw promise in Ryu-Yeon and asked him if he would like to become his disciple. As Ryu-Yeon had nowhere to go and wanted to make the most of his life, he accepted the old man's offer.

Eunho, the strongest in the yokai realm!
He gained the chance to become a human being after losing the woman he loved and killing countless yokai.
After passing the gate of reincarnation by accumulating merit for a thousand years to abandon his immortal body…

He became a human being, held a sword, and learned martial arts for the first time.
But this is very… easy?

Balud Cornelius is the son of a noble of the Mauricia kingdom and inside him also dwell the souls of the stingy warring states commander Oka Sadatoshi and animal ear otaku high schooler Oka Masaharu. With these 3 souls in a single body, he can exhibit extraordinary abilities when it comes to combat or managing the domain.

Kurogane Hayate finds herself in a dilemma. Her twin sister, Nagi, is recovering from an injury and needs someone to go to school in her place. Little did she know, the school was based on a "Swordswoman League," where everyone participates in what are called Duels for Stars with their sisters-in-arms, shinyuu, in order to gain prestige, money, and power.

Her first encounters with the students at this new school range from intimidating, such as with the Student Council President, Amachi Hitsugi and her shinyuu, Miyamoto Shizuku, to completely awe-inspiring, such as the hot-headed but extremely experienced (shinyuu-less) Mudou Ayana. At first Hayate thinks she can get away without participating in the Duels for Stars, but the first day she comes home, the orphanage she cares for deeply is a complete wreck...

Im Hwapyung. A man who wants to live a normal life like his name. Everything he had in his mundane life was destroyed. [Your love has become my loathing.] You shouldn’t have messed with me in the first place. You should have just let me live a quiet life. And now he has began his move that none of his nemesis will survive his wrath.

In the whole world there lays twelve paths to climb Tower of God, and in legends these twelve pathways leads toward legendary road of immortality. However these paths in the Tower of God, are far too long, without end. In ancient times there once were many types of martial arts, sadly the world underwent terrible changes, and only three were left: Flame, Dragon and Star Martial Arts. Generations of experts of those three martial arts are searching for the road of immortality.
A Star Martial Arts practitioner on his journey of lifetime, plans to become the Highest God.

A spin-off manga created by Toyotarou, and based on the arcade game Dragon Ball Heroes. It debuted in the November 2012 edition of V-Jump, the release date of which was October 20, 2012.

http://dragonball.wikia.com/wiki/Dragon_Ball_Heroes:_Victory_Mission

He learnt the strongest martial arts only to be killed and be reincarnated as a rural village officer as Master Baek, The One Hit Teacher!

Nam Ji-il rolled into the high school that is famous as the Royal Kingdom of the delinquent. On the first day of school, he becomes a well-known bread shuttle boy in the entire school. While suffering from chronic heart disease, his weak body also has to suffer from assault any other kind of bullying, however, caused by an unexpected event his life reaches its turning point...

Spin off of main series Senran Kagura - Shoujotachi no Shinei, it portrays the main storyline from the point of view of the snake girls, and follow their misadventures, victories, and defeats when confronting Hanzo ninja, being released in Comic Rex. Different point of view from main story line, with main actors being the snake girls with focus on their academy.

You called me. A person like me "Brightness of Hermit". Become an escort!

Ryouma Takuma, a 39-year-old man with a hidden past, finds himself in a strange white room. The gods tell him that he has died and they are sending his soul to a different world, a world where magic exists. Living alone for 3 years, his gamer soul loses common sense and starts heading toward crazy routes.

There was someone who set out after receiving orders from the Absolute One who first unified the continent to learn the secret of immortality. He believed that he would definitely discover the secret of immortality even if he had to travel all over the world. He never returned until the Absolute died and the empire collapsed, leaving behind only numerous speculations and gradually being forgotten in people's memories. And after a long time...

Devoid of any talent, I met my end after suffering at rock bottom for many years.

That was my first life... and the start of my endless regressions.

A karate practitioner who has been transferred to another world refuses the cheat skills given by the goddess, and he pursues his own karate in another world.

I want an S-Rank skill too! I want it so badly, I could die for it!

[You have awakened an S-Rank skill.] [But it only works when you die.]

HUH!? WHAT’S THE POINT OF GETTING ONE IF I DIE !?

1st Trailer: https://www.youtube.com/watch?v=Sz51IU05F88