Able's father.

A demon of a high rank.

He met Catherine while traveling the human kingdom (disguised as a human). As their relationship progressed, Hazel decided to inform Catherine that he was a demon, despite knowing she would probably leave him. Since most humans had a very poor outlook towards demonkind due to their religious teachings.

To Hazel's surprise, Catherine wasn't bothered by the knowledge. They both knew Hazel would have to go home eventually and he would have to leave Catherine behind. Hazel stayed in the town for several months before he ultimately had to return to the demon country. Completely oblivious that Catherine had become pregnant. It wasn't until Hazel got the opportunity to converse with the hero years later, that he started to connect the dots.