Gabriel Miller was born in the Pacific Palisades district in the suburbs of Los Angeles, California, in March 1998 and is the chief technology officer of Glowgen Defense Systems and the child of the former president and founder of the company. He was the winner of the 1st and 4th Bullet of Bullets tournament in Gun Gale Online.

Gabriel is obsessed by the human soul, even killing his childhood friend Alicia Klingerman to catch a glimpse of her soul as she dies. He shows great interest in the FullDive technology created in Japan in his pursuit of souls. He even began studying Japanese and fought against Japanese players in Gun Gale Online as Subtilizer. He was a legend among GGO players, as he was able to win the 1st BoB tournament with just a knife and a handgun and win the 4th BoB tournament without bringing any weapons of his own, using the Army Combatative skill to grapple to his opponent, steal the player's weapon and use it to kill his target. He is somehow able to predict the moves of his targets to ambush them at extremely close range and to kill them before they are even able to use their weapons against him.

One day, his company was approached by the National Security Agency and they were requested to participate in an operation to assault the Ocean Turtle to obtain the Soul Translator technology secretly developed there. Hearing about the technology to interface with the human soul and that it had already succeeded in duplicating a human's soul, Gabriel volunteered to lead the operation himself.

In the Underworld, he is known as Vector, the god of the dark territories. Gabriel plans to steal the Soul Translator technology in order to create his own virtual world where he can analyze souls. In order to achieve that goal, he plans on hunting people with strong souls, especially the Sword Art Online survivors', and steal their Fluctlights.
(Source: Sword Art Online Wikia)