MTL - The Human Emperor - Chapter 2359 Temple of Heaven!

Zack “Kazz” Foreman once was a human from the earth when humans went through a dramatic change because of an event. This forced them to evolve into energy-based beings but was sucked into another dimension.

Forced to start living out lives on random worlds in a fractured dimension, Humanity is placed on the path of complete extinction.

This is controlled by a demon king at a place called The Center of Everything.

The Demons try to force Humanity's mark from every reality, so there are only demons, but the Demon King feeds from anger and pain. A constant tournament going at the center of everything to feed his hunger.

Kazz made it to that point once, but was tricked, refused entry to the tournament because he had offed a place one of the gods of the worlds.

Refusing to give up, Kazz goes back to the beginning to start again. To do this, Kazz must give up all of his memories to choke the flow of demons born fully grown from a pool of recycled souls.

This journey starts after he lives a solitary life trying to get stronger but not knowing why. The world Kazz is on is like our earth, but it was only a mimic of the earth we know.

Caught using steroids and about to give up and join the army, Kazz stumbles onto a cave in the ground. He is transported to a world filled with demons and monsters, and a human god named Hero is speaking in his head.

Hero, a person Kazz knew but was not friends with, followed him to help but was lost from him. Upon meeting Kazz, Hero offers him the Hero System to help him advance in this new world.

Kazz refuses after trying to get to the top and failing to use the easy route. This starts a series of frustrating events for both Heroes, but they learn to work as a team over time.

Kazz will meet misbegotten monster girls and demons that he agrees to take care of in this world, using the Ranching System. It only gives bonuses to the girls and skills to help raise them, but he will also learn to control the Elements with Shamanic abilities.

In novels with a stud there is always a Senior Martial Brother like this:

In the early stages of the novel, his innate talent is high, his cultivation is good, his appearance is handsome, and he has an intelligent, cute younger Martial Sister as a fiancée.

In the middle stages of the novel, he is caught unprepared and defeated by a young disciple (the protagonist) in the sect who’s hardly remarkable at all. From then on, he falls from his godly altar and loses his brilliance. Even his young Martial Sister leaves him for someone else.

In the late stages of the novel, he continues to turn dark, going down the Demonic Path and becoming the major villainous boss. However, the protagonist still ruthlessly defeats him and his soul is eternally sealed.

Once Qin Mo opened his eyes, he discovered that he had become this Senior Martial Brother.

- Description from Novelupdates

On a certain day, a certain thought came to Japan’s Sun Goddess. ——Aren’t there too many Japanese people being abducted to other worlds? It’s true that the large majority of Japanese are diligent and docile and soft-hearted, which makes them pretty much the best people to ask for favors. “But recently it’s just gotten way too out of hand…… Oh, I’ve got it! Whenever a Japanese person is summoned, I just have to summon an otherworlder!” And now, every time a Japanese person is summoned, princesses and elves and beastmen and whatnot are reverse-summoned. Under the acknowledgement of the government, they begin living in Japan. Today, too, Japan is at peace. And so begins this laidback isekai cultural exchange story♪

After the gold medal teacher, Sun Mo of the city’s No. 2 Middle School, fell into the water, he transmigrated to Tang Guo, Zhongzhou Academy and became a newly graduated intern teacher. Sun Mo bound the Peerless Master System, turning waste into little geniuses. Under Sun Mo’s guidance, the little children became masters after one year, passed emperor level after three years, and attempted god level after five years.