Apocalypse Chaos - I am the villain - Chapter 191 Why?

One day, Zhang Fan, a poor medical student, receives a medical system from the future. This turns him into a new shining star in the medical field. Along the way, he must face medical corruption, competition, and infighting from other doctors, and even find time for a love life as he strives for the top of the medical field!

- Description from Novelupdates

Mystery is the nourishment that keeps me from being ordinary.

It has been 20 years since he came to a world similar to the modern European background. With his early wisdom, Fei Lin learned a skill and finally became a decent person.

Originally thought that he would marry a wife and have children and live this life in a dull way, but found that there is another world under the shadow of the world.

In that world, there are occultists who practice esoteric techniques and master extraordinary powers.

It is weird to spy on humans in the dark and feed on humans.

There are evil god believers who worship the evil god, please the evil god through bloody sacrifices, and exchange power from the evil god.

There is an evil god who wanders outside the world, peeps at the world, and only infiltrates the power of scales and claws, which is enough to cause people to fall.

With the mystery as nourishment, he is no longer ordinary after 20 years of ordinary.

- Description from novelbuddy

He died on the wedding of the girl he had a crush on, after a long and successful career. After convincing Yama to send him back to the world, he decides to fix the areas in which his life went wrong. Realizing the lack of love and romance in his past life, he sets out to conquer the hearts of various women.

I, Hyoudou Issei, am a 2nd Year High school student and my age is equal to the number of years I haven’t had a girlfriend. And, someone like me got a girlfriend! I’m sorry buddies, I will walk the path of becoming an adult before you guys! – That’s how it was supposed to be, but why did I get killed by my girlfriend!? I still haven’t done anything yet! Are there no Gods in this World!? And, the person who saved me is the most beautiful girl in my school, Rias Gremory-senpai. I learned the shocking truth from her who isn’t a God but a Devil. “You have reincarnated as a Devil! Work for me!” Lured by Senpai’s breasts and treats, my life as a reincarnated Devil began. So the “Academy×Love Comedy×Battle Fantasy” starts here with just aggressive and worldly desires!