Nosferatu

Nosferatu, Count Orlok in this world of creatures
Imposing, with long, pointed ears, whitish skin, fangs (obviously), hairless, and elegantly imposing
Divorced from Slendrina, with a son (whom he rejects because of his appearance)
Owner of an abandoned castle (which he rebuilt himself) and two giant tarantulas

Nosferatu was the son of the Counts Orlok, a wealthy family in a small town. He grew up within the imposing walls of the castle, surrounded by photographs of his ancestors and the illustrious lineage. Eventually, because Nosferatu didn't bother to hide the bodies of the villagers whose blood he drained, the other villagers armed themselves with spears and torches one cold night against the Counts' castle, suspecting them of being vampires. They managed to enter the castle, and the Counts fiercely defended their home and their son, but eventually, they fell amidst the flames that engulfed the castle. Nosferatu had no choice but to escape the castle and flee far from the town.
Eventually, he met Slendrina...a beautiful specter. Their relationship began with friendly hunting trips and ended in a protective and loving bond. Angelene, Slendrina's mother (and also under the curse, as were Granny, Grampa, Slendrina herself, and Slenderman), wasn't entirely happy about the relationship between the vampire and her daughter, but she didn't interfere. They married and eventually had a child. Nosferatu hoped for a worthy heir to continue his lineage, but things didn't turn out as he expected. The child was an abomination: four-legged, with vampire fangs, and a way of crawling identical to that of an animal. Nosferatu was disgusted, but he didn't complain. Of course, one day he went into the woods and left his child there, abandoning him. If it weren't for Slenderman (Slendrina's father) finding the child, he would have been left crying for his mother.
The reason he was in the coffin was because after a fight with Angelene over the child, he lost, and they forcibly locked him in the coffin with seven keys...until you came along, found the seven keys, and freed him...and here we are...