Milo McLaggen/Background

Milo is the son of Philomena Mordecai's third cousin Agatha Morgenstern (vampire) and the demon Marax. The boy was born just a couple of months later and was raised by his mother in a castle in Romania. It turned out Milo wasn't neither a vampire, nor a demon. However, he possessed the powers of both which later, after his special vampire power showed up, made him invincible. Even though his mother was afraid of him and his abilities, she took care of him for a century. She kept him a secret in fear of her family killing her and her son. 
At the age of 102, Milo went looking for his father and when he finally found him, he killed him without blinking an eye. He hated demons and killed every one he met. When he came back home, he was introduced to Philomena - his aunt who could keep an eye on him while his mother was with her family. Milo was upset because after all these years Agatha hadn't told anyone but Philomena about her demonic child and so he was ready to follow her and kill her whole family. However, Philomena stopped him and since she was the only one who wasn't afraid of him, Milo started liking her and shared everything with her. 
A whole year passed before he had any news from his mother. One day, his grandparents came to the house and Milo knew that Agatha was probably dead already. And before the old vampires had the chance to say or do anything to him, Milo used his special power to call out all the demonic energy and use it on his grandparents until there was nothing left of them. Philomena decided to leave the castle with the little demon and she thought of him as her son from that time on.
They lived together in Greece and Milo was happy. He even met nice vampires there but never befriended them. Most of all, he liked the dark haired vampire clan McLaggen. They were all cool and nice to him. So when they left the country, Milo decided to take their last name and hide that he was from the Morgenstern clan because he still hated them all. 
Years passed and Philomena brought another misfit in their home. Milo met his cousin Madison Oberlin. The girl was also unwanted by her family and Philomena was her last hope. Milo didn't like the blonde girl at first but after a while they became very close just like siblings. 
When the trio went to Charmedsity, Milo didn't want to leave the house and stayed in secret until Philomena told him that there was a McLaggen in the city. In the night, Milo went to see if it was true and he was left speechless when he saw Cormac McLaggen - a blonde heir of the vampire clan who had become Death. The town got a bit more interesting for Milo and he started going out more often - usually in the night. He went with Philomena and her ballet to rehearsals and there met a little vampire called Pepsi who told them all about the city and its habitants. It was all too weird and complicated for the demon so he preferred to stay at home with Madison until Hannah de Vil showed up. It turned out she was the Devil and she wanted to control him but he showed her not to mess with him. However, he did make a promise not to kill her demons and Hannah stopped annoying him.