Onyx, birth name James Adams, born in Liberty City to a very rich and successful businessman and his wife. He grew up in the Hatton Gardens in Algonquin. Although it would seem Onyx had the best life possible growing up, it was anything but. Onyx's mother had a disdain for him because she wanted a daughter and not a son. While his father tried his best to be a good role model for Onyx and take care of him, he was often working late nights or gone on business trips, leaving Onyx alone with his mother. She would frequently yell at him and emotionally abuse him.

When Onyx was 12, his father was home, which was a very rare occurrence. Onyx wanted to go to the local park and spend time with his father playing ball and begged his father to go with him until he finally caved in. On the way to the park, Onyx's father was mugged and shot dead in front of him. Onyx blamed himself for his father's death and fell into a deep depression. His mother also blamed him for his father's death and would constantly tell him he's the reason he was dead. She also started to physically abuse Onyx on a regular basis, leading to many unexplained hospital visits for injuries ranging from bruising and bleeding to broken bones. After 2 years of constant abuse, Onyx finally had enough and ran away from home at the age of 14. Onyx began to turn to petty crimes as a means of survival. He started to shoplift and steal money just so he could afford to eat and drink. After he was caught trying to pick pocket from a mob boss, the mob boss was amused and decided to take Onyx in and see how he faired in a true life of crime. Onyx seeing this is an opportunity to get out a life of petty crime and being homeless did not hesitate to join.

Shortly after joining, Onyx met the dons daughter, Bonnie Burn, who he fell in love with almost instantly. He and Bonnie began to date in secret out of fear of what could happen if Bonnie's father found out Onyx was with her. Onyx slowly began to work his way up and became an enforcer, carrying out the mobs dirty work for them. He became more ruthless and cold, frequently volunteering to go out to either collect money from those that owed the mafia or go murder someone that they needed gone. Around this time Onyx also began to secretly pocket a portion of the money he collected from those he beat or killed.

After Onyx turned 18, be began to fear that the Don would soon realize that not only was Onyx was stealing from them. but was also in relationship with his daughter. decided to flee the city to Los Santos and change his name to Onyx Steele. Shortly after arriving in Los Santos, Onyx moved into the South Side of Los Santos and soon joined up with the Ballas. He began to work his way up quickly in ranks.