A future of people called hunter who go through dungeon that appeared out of no where

And they hunt monsters. There is a saying among them: "To kill monster, you have to become the same." They change into something new. After they are reborn, they call themselves Hunter-Men and live. But there was one man who didn't want to become a Hunter-Man. He wanted to be human. So he put on a mask that would make him look like a human.

Masks are worn by men who don't want their identities known.

He found a dungeon that has a alter inside he found something that only normal humans can have women. A woman named Mary. From then on this man, called Riza, lived in the dungeon with her. Riza was attacked by the other hunter but he fought back and won. The reason for his victory is because he discovered a secret skill, which made him stronger than others.

Because of that he gained more power. And then he got the title of King.

Riza became a king when he was just 18 years old. He had a beautiful wife with long blonde hair and blue eyes named Mary.

10 year later...Mary died in childbirth and their daughter was born. She was a girl named Saya. Riza gave all his attention to raise his child.

There were rumors about a strange man who lived in the forest near Riza's castle. And then a rumor spread that said that he ate children.

The villagers told Riza that they are worried for their children and so he went to the forest to find this man. When Riza arrived at the forest, he was captured by the masked men. They tied him up and brought him to a cave in the mountain. Then they asked him about what he was doing in the forest. But he refused to answer.

Then they took off his mask and put it on.

The face they saw was of a Demon but when they put on riza masks black started coming out of the mask then a fight happens between demon and Riza. During the fight Riza discovers that the demon is actually the man who used to live with him before. His name is Mika. He was also a king like himself.

After the battle, Riza gives Mika the mask.

Mika takes off the mask and puts it on. The face he sees is of an old man. After that he asks him why did he leave the castle.

To protect my daughter then the masks mika put on black glo that was acid that started melting his face he tried to stop it but he couldn't.

Riza tells him the story of how Mary died. And that his daughter was born.

Then he walks away from mika corpses in the cave then he hears a girl crying. It turns out that she was Mika's daughter.

Riza takes care of her and raise her as his own daughter.

20 years later...Saya starts getting older and grows into a beautiful young lady. Riza has never seen his daughter grow up.

One day Saya goes outside and sees a Hunter-Man who looks exactly like Riza. He calls him father.

After that incident Saya becomes depressed. She doesn't want to believe that her real father is dead.

She tries to escape from the castle. But she gets caught and brought back to the castle.That night Riza comes home and see something in front of him.

It was a girl, but not his daughter.

He didn't know who it is until he saw the mark on her forehead.

That mark was the mark that a person who has been reborn as a hunter carries.

It was the mark that everyone called the mark of the Hunter.

Riza realizes that this is his daughter.

Then he takes her to his room and tells her everything.

I love my daughter very much but I need to tell you a secret.

My true identity is Riza.

But my real name is Mika.