In the MCU/Marvel with the Omnitrix/Ultimatrix - Chapter 23: Two Geniuses One Project

220 years ago, in the legendary Dragon Demon War, Hero Azell ended the war by killing the evil Dragon Demon race’s King Atein. He was able to save the population, but as a consequence, he was cursed. While he was dying, the high magician suggested a gamble that might save his life.

Part 1:

On April 3rd, 2019, there was a virus outbreak and the cities were besieged with zombies.

A month later, on the national road outside H City, Shen Shian carried a heavy sword and walked around the vehicles abandoned everywhere.

“Don’t make trouble,” he said while turning back. “Keep up, the sky is becoming dark.”

“Hey!” A child who looked to be only four or five years old answered. He slashed the sword in his hand and cut the head of a zombie. Then he reached in and pulled out a marble-sized transparent crystal.

After rubbing it a few times on his clothes, he carried a Tang Sword that was half the height of an adult human and ran to Shen Shian.

“An An, I’ll give it to you!”

Part 2:

Shen Shian picked up a miserable puppy with dirty and knotty fur and a terrible smell.

The first time he brought the dog into the spirit spring, the dog turned into a child.

The second time the child was brought into the spirit spring, he turned into a man.

On the edge of the misty spring, Shen Shian looked at the man swimming and asked with a frown, “Can you change back?”

“Why?”

Shen Shian pursed his lips. “…You will eat too much.”

The man wrapped himself in a bath towel and emerged from the space with the Tang sword. After a short while, he inserted the sword into the grass and handed Shen Shian a handful of sparkling crystals.

“I might eat more but I am also more capable!”

- Description from Novelupdates

—She is a girl with a bright smile on the battlefield.

With her silver hair fluttering in the air and dark eyes, the girl sprinted on the battlefield. Her name is Olivia, whose hands is stained with the blood of her enemies as she shows an innocent smile.

The deep knowledge and combat techniques of the entity who called itself a Death God has been branded onto her body. On Olivia’s 15th birthday, the Death God suddenly disappeared. Olivia enlisted with the Royal Army and started fighting in the war as she searched for clues.

Lunar Calendar Year 998. The Kingdom has suffered consecutive losses to the Empire aiming to conquer the entire continent. The innocent girl who lacked common sense will step into the battlefield as the “Strongest Chess Piece” of the Kingdom, and go down the path of a hero—!

Once upon a time, a hero had been summoned to a different world in order to defeat the demon king. After the war stretching 3 years ended the commendable hero slew the demon king. And he was forcibly deported back to earth after being dismissed.

Such bullshit!

Elves in addition to beast race, dwarfs and demon race. Even though I wanted to make a harem in the different world I saved! My dream will not come true on earth, where there is no magic at all. Thus, the hero returns on his own. Without the blunder of being extradited to earth this time, he will build a harem of his own in a different world.