Billionaire's Secret Twins and Rebellious Wife - Chapter 45 - 0: The Origin of Little Chenxi

After his qi center is destroyed, a martial arts instructor of the Blood Demon Cult is assigned to learn and research the martial arts of four captured murim masters. However, when the Cult betrays him and decides to kill him, he fights back and everyone in the Cult dies, including himself.He then mysteriously wakes up in the body of Baek Suryong, a young martial arts instructor in the rural countryside with a disease that will kill him within three years. He realizes that the martial arts he had learned holds the key to healing his new body’s illness, but in order to do that, he needed money. A LOT of money.Baek Suryong thus embarks on a journey to become the Star Instructor of the Azure Dragon Martial Arts Academy, and earn enough money to save his own life! Perhaps he would even manage to educate some kids along the way…

An 18-year-old poor college student tried to apply for a job as a tutor but his life almost ended as demons' meal. In his last breath, a mysterious woman gave him a strange power. When he opened his eyes he had turned into a demon with a system that would turn him into… A pervert.

Now he must lived with his dual identity as a model student named Ethan and an incubus named Damian.

Luo Zheng is at the bottom of the Luo Clan hierarchy, despite his family being the founders of a power refining technique that could instantly defeat any opponent.

One night, enraged by unfair treatment from a family steward, Luo Zheng burns the family records. In doing so, the hidden magic in the book engulfs him and Luo Zheng becomes a new skilled fighter. Fleeing his home and despicable clan, Luo Zheng must learn to harness his powers to rescue his younger sister while his own cousins are on his pursuit.

- Description from Novelupdates

Ryu Han-bin, the main character who fell into a new world after being chosen as a ‘suitable person’.

Because of the error in the guidelines, the training is repeated endlessly…