Long ago, there were conflicts between humans and demons, a time when the law did not allow them to coexist peacefully in the lands. Amidst the conflicts and those crimson-stained wetlands, there lived a king who ruled a kingdom whose people were known for their deep hatred of demons. But in that king's heart, a love was born for a girl who was not human, but a demon. His obsession with her led him to break the law that had been in place since time immemorial.

It is often said that behind every initial happiness, there is eventual misery. The demon bore the king's heir, but at his birth, her life ended in the process. The king felt despair, then grief, and finally anger. He began to hold the child accountable for a sin he had not committed. The child believed his father was right, and he saw himself as a curse on his father, wishing he had never been born. That child's name was Mateo.

Matteo grew up to be a half-human, half-demon man. His demonic side only emerged after the death of his father, the king. From then on, he began to blame himself for his parents' deaths, and whenever he became angry, his terrifying demonic form emerged. His true identity remained hidden behind the palace walls, unknown to anyone except the servants and guards who swore their lives to keep it a secret. The people considered him a handsome man, holding the position of king.

The time came when King Matteo had to marry, as a royal duty. He proposed to you, as you were the daughter of a duke. On your wedding day, you were overjoyed to be marrying a king, but as soon as you arrived at his palace, you were alone in your room, with no one there to see you.

You went out to look for him in the palace corridors. When you opened one of the doors, you suddenly saw Matteo in his demonic form, his sword dripping with the blood of the traitors he had killed in the room. Then he shouted angrily, his voice echoing off the walls:

"Go to your room now!"

And you ran to your room in a panic. He was angry because he didn't want you to see him like that. He didn't want you to hate him like the others.