Sovereign of the Karmic System - Chapter 15 The Building Owner

A good-for-nothing man married a beautiful girl but was kicked off the bed on the wedding night. Furiously, he wrote a bill of divorce and ran away.
He was schemed a car accident in which he nearly lost his life. However, it turned out to be a blessing. He swallowed the soul that passed through the outer world, thus obtained superb medical skills and martial arts.
Later on, with the silver needles and invincible martial arts, he embarked on the road of counterattacks and was committed to his great dreams.

- Description from Novelupdates

Choi Hyun-seok, a heavyweight champion of the biggest mixed martial arts league on Earth and the one who was called the strongest had died.Afterwards, he was granted new life as a hero in another world.‘Wealth! Honor! Endless beauties at your fingertips!’With thoughts of such a dazzling future, the first thing that he saw when he came to this new world was a towering ox monster.The monster, who was the commander of the demon army, asked.“Hero? You’re saying you’re the hero?”“Uh…I think…?”And so, that was the start of hell.

After the brutal loss of his beloved grandfather, Liam Hunter embarks on a harrowing journey into the heart of the Dark Forest, known as the Forest of Kyrell, with a singular goal: to gain the strength necessary to honor his grandfather’s memory and to never lose anyone dear to him again. At just ten years old, Liam is thrust into a world of darkness and malevolence, where he endures four grueling years of training and transformation. In this shadowy realm, he is reborn as a fierce warrior, driven by a relentless desire to eradicate every demon and ultimately confront the Demon King, Emrys himself. To achieve his formidable goal, Liam must forsake any emotional connections that could weaken his resolve. The once vibrant and joyful boy is transformed by his trials into a cold and unfeeling combatant, hardened by the harsh realities of his quest. This is the story of Liam Hunter—the last wielder of dark magic—whose journey through darkness and sacrifice will shape him into a force of vengeance and resolve.

An ordinary student accidentally traveled into an other universe and became the king of a small kingdom. He had gotten a “Cheating Code” of life and was able to complete something extraordinary. This is the story about a king that was able to conquer continents and leave behind him an ultimate legend that will be recited between every generation to come.

- Description from novelupdates