Colton O'Neil

Colton O'Neil (コルトン・オニール) is the original main character of Arsenal and the first main antagonist of Ultimate. He was the twin brother of Hunter Bradley, younger half-brother of Amanda O'Neil, and the son of the late Barry O'Neil and the late Samantha Bradley.

Growing up with his father and older half-sister, Colton watched his city become corrupt and filled with crime, and became the fierce vigilante known as Arsenal, aided by Amanda, Jared Wilcox, Whitley Abbott, professor Rick Grayson, and later Hunter. However, he was seemingly killed by Deathshot, and his mantle was taken by Hunter.

Unbeknownst to everyone, it was revealed that he was not killed and was recruited by The Hierarchy to become their Sentinel. Leaving the Hierarchy, Colton sought out the Anarchy Spear, in order to alter reality and rule the world, creating Helix in order to kill the opposing Legends. He was eventually able to successfully unleash Prometheus.

Engaging the Legends, Colton gained the upper hand on Hunter and upon the intervention of the Alpha Rangers, Hunter was forced to kill Colton, much to his distress.

Personality
After Deathshot and the Hierarchy faked his death, Colton suddenly became very cold and indifferent. When Hunter confronted him with the files of him being an agent for the Hierarchy, he apathetically told him all of it was true with no guilt or remorse whatsoever. The love he had for his friends and half-sister had vanished too, as he shows no sorrow when Hunter shows him pictures of them and Hunter even remarks that a real man would have asked to see photos of their family.

Once Hunter took Kate's advice to treat him like a brother rather than a criminal, Colton started opening up and becoming more responsive. He later seemingly redeemed himself when he helped Hunter save Gavin. However, this redemption quickly proved to be nothing more than a façade, as Colton was still in contact with Helix, and when confronted about his new betrayal by Hunter, Colton scoffed at Hunter's continued refusal to make the "necessary" choices. Forfeiting all personal ties to his family, he declared his only family was Helix, with pride.

Showing how far his morals had dropped and high his desire for power had become, he tortured his older brother with sadistic pleasure after acquiring the Anarchy Spear and unleashing Prometheus, and openly declared to kill Kate and the other Legends. Through intervention by the Alpha Rangers, Colton was defeated by Hunter and the Legends, and initially attempted to feign remorse. However, he ultimately still met his end by his own twin brother's hand.