Dylan's father, Hugo, was a piano prodigy. He was a famous musician who played all over the world by age fifteen. He lived in New York in the famous Dakota building, already coming from a wealthy family. As the only child and eldest grandson, he became head of the Angel family when his father and mother passed away in a car accident. When Hugo graduated from Julliard, he began to focus more seriously on his career. One concert in Berlin, he was arranged to do a duet with a violin player. The violinist was Cybele in disguise. Hugo had caught her eye when she had seen him play in concert when passing through a city he had visited. Hugo thought that Cybele, under the name of Cassandra Lee, was a very beautiful woman. He was instantly drawn in by her beauty and the beautiful music she played. After the concert, he invited her to the pub to celebrate. The two got drunk, and Hugo invited her to stay with him at his hotel that night. Obliging, one thing led to another and Dylan was conceived. Hugo woke up with an awful hangover, completely forgetting what had happened. After his memory cleared up, he wanted to apologise to Cassandra for a 'straight to third-base' kind of date, but was unable to find her. Thinking he was out of luck, he went back to New York without seeing her again.
Months passed and Hugo was more successful than ever. It was the peak of his career when a swaddle appeared on his doorstep one winter morning. It was an infant, and he immediately panicked and brought it in. He paled as he remembered that one night in Berlin, when he was drunk and brought that violinist home. This must have been her child. His child. But Hugo was not compassionate. He was actually quite angry. Why would she dump the baby on him? She had left him and now it's his job to care for the child?
He tried to contact Cassandra, but it was like all evidence that she ever existed was wiped out. He contacted the front desk, asking them if he was able to take a look at the cameras to see if she had passed. But even with that, there was no evidence. An empty hallway and suddenly the baby was there. There was no trace of her in other camera's film either. He was totally against abandoning his own child and sending it to a children's house, so he hired even more staff in addition to the many maids and butlers he already had. He named his son Dylan Arthur. A young woman who was a daughter of Aphrodite was Dylan's primary caretaker. She wasn't aware that Dylan was a demigod.
When Dylan was old enough to walk and talk, Hugo began to teach him how to play piano. He was a fast learner and was learning pieces most adults with have trouble with by the time he was in kindergarten. Hugo and Dylan had a very close relationship, even with Hugo having to travel and leave Dylan in New York for performances. He also grew closer to Jade, the demigod daughter of Aphrodite. Hugo was entranced by her beauty, but it was going to be out of line for him as the head of the Angel family to have a relationship with someone like Jade, who worked for his family. So the two had a secret relationship. Meanwhile, Dylan was growing up as a very mischievous child. He never let his wealth get to his head, but he did like playing tricks on the house staff and everyone else who lived in his family's luxurious apartment. However, they all regarded Dylan fondly, despite how often he got on every single on of their nerves.
When Dylan was ten, he was sent off to a boarding school in Manhattan. It was a long family tradition to send the boys of the Angel family to the same boarding school generation after generation. He would be there until he graduated high school. Dylan came home for the holidays and visited on every other weekend. Other than that, he was rather enjoying this boarding school life. He was a popular student and was very well-regarded as a student despite his tendency to make other teachers want to expel him for his antics. He used his good looks to get any girl he wanted to fall for him, usually just flirting with her and moving on in a very short time.
He was best friends with a boy named Ryan. Ryan was secretly a satyr, as this school had a reputation for hosting demigods. When Dylan's first monster attack came when he was thirteen, he was hanging out with Ryan and another demigod named Lila James. Lila was a daughter of Hades, and she and Dylan were dating at the time. Lila had already been to camp the previous summer, already learning the basics of defense. She carried her Celestial bronze sword in the form of a bronze heart shaped locket. After Ryan had revealed that he was a satyr and that Dylan was a demigod, she agreed to hang around him and Dylan. They were out when it got dark, walking home from the mall through a park. There was no one there, and a hellhound had caught their scent. Lila, true to her training, was able to take it down when it had tried to pounce on Dylan.
Lila and Ryan explained everything to Dylan. Dylan, being the 'go with the flow' kind of person took it easily, shrugging it off as if it was nothing. He actually found it another opportunity to tease at his dad for hooking up with a goddess and not knowing it and the whole idea of being half god was really cool to Dylan. They contacted Hugo to let him know. Hugo, knowing of Dylan's prankster nature, was totally not convinced. However, Jade was listening to Hugo talk and revealed that she was like Dylan. This was enough to convince Hugo that Dylan wasn't joking for once and the three told him about Camp. Hugo wanted Dylan to stay in the school until he was fifteen, so he didn't want Dylan going to Camp at the time. Lila was able to teach Dylan a few self defence tips against monsters. When she came back from Camp that spring break, she also made sure to bring back a set of bow and arrows with her for Dylan. It took the form of a silver puppy keychain that can now be seen attached to Dylan's belt loops on his pants or in his pocket.
Dylan stumbled across a few minor monsters in the two years he had lived without going to Camp. Luckily, he was a fast learner. He did surprisingly well for an amateur with his bow and arrows, only using the guidance Lila had given him and a few self-taught tricks. At fifteen, his father agreed to let him go to Camp in the summers, where he further expanded his skills. Slightly more difficult monsters came to attack him at his time off of Camp, but Dylan was able to handle them very well. His seventeenth birthday passed and he was a school year away from graduating high school. Dylan couldn't possibly wait any longer - he wanted to be like Lila who had started going to Camp year round by last year. With enough persuasion and thorough thinking that it was after all only one year until Dylan was due to graduate, Hugo gave Dylan his permission to stay at Camp.
Dylan was picked up by Lila, who had traveled to school campus and went with him to take a cab to Half-Blood Hill.