The Undead King of the Palace of Darkness (WN) - Chapter 57

Roy died during a war against the Evil God Cult, but somehow, he returned back in time to 30 years in the past where he was just a boy who awaken his summoning magic.

An ordinary student, a wretched peeper, a cowardly teenager with a kind heart. In a terrorist attack, he inherited the knowledge of countless elites, embarked on a path of God Jagged Tu…

He is an artist!

He is a mathematician!

He is a psychology Doctor!

He is a master of fighting!

In fact, he is a man

Taken off raw site:

A wretched, dirty young man is working during the summer when he was caught up in a mysterious explosion. After that explosion, the young man is then left with the memories and knowledge of dozens of the world’s experts.

He has changed, his heart has become cold, iron-blooded. He became a killing machine, his mind turned mechanical, calculative. Everything goes according to his plans and calculations!

In this magical, slaughterous world, a door is opened for him…

- Description from Novelupdates

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