Brady O'Brien is a S.H.I.E.L.D. agent who worked with Phil Coulson and Melinda May during a mission to capture an Inhuman, during which O'Brien and his team were briefly brainwashed. After the capture of Robert Gonzales' S.H.I.E.L.D. base, he was sent to monitor the agent Fitz who expressed a desire to leave S.H.I.E.L.D.. Later he assisted in the attempted killing of Hive. However O'Brien was later caught in a trap and transformed into one of the Primitives with a bomb containing the Absolution Virus. After been subdued, he was later freed from Hive's control after the dark Inhuman's death.
Agent Brady O'Brien was assigned to the case of Eva Belyakov, a gifted individual and Index candidate who was to be evaluated and taken in by S.H.I.E.L.D. before a different government agency could. He traveled to Bahrain under the command of Agent Hart and with Agents Phil Coulson and Melinda May brought in to help.
Brady watched Coulson try to reason with Belyakov and was instructed to make sure a group of locals, who had been put under the coercion of Eva Belyakov's daughter, Katya, did not interfere with the mission. Eva Belyakov caused a large commotion which resulted in O'Brien and the Bahraini men pulling guns out at each other. One man grabbed Katya Belyakov, so Brady went with the thugs so the girl would not be hurt. O'Brien became part of Katya's thrall, and answered Coulson's phone call simply telling him to leave them alone.
The rest of the S.H.I.E.L.D. team that went in were put under Katya's power, and O'Brien fought Melinda May with them. They were brought into a room by Katya following the death of her mother, where May shot the girl before she could kill Brady and the other agents and brought them out of her trance. Brady could not remember any of the events from when he was under Katya's spell; he only remembered seeing all of the dead men on the floor when he regained consciousness, starting rumors about the infamous tale of May's nickname, "The Cavalry".
Battle Against Hive
As S.H.I.E.L.D. found the location of the Inhuman Hive, O'Brien, Piper and two other agents volunteered to join Melinda May and Alphonso Mackenzie to kill Hive. Mackenzie briefed the agents about the mission and they used Zephyr One to go to Union City. On Zephyr One, Director Phil Coulson also briefed the team about their mission and asked them to be careful and smart.
Upon arriving to Union City, May got the information about Hive's location. As the team went to there, Brady asked why Hive had bought a town and not working in the center. They entered the facility where they saw the Kree Orb in action. Coulson ordered the team to get out quickly. As they were out, a satellite crashed directly at the facility. Brady informed the team that there were big footprints.
The team followed the Kree Reapers, who killed everyone they encountered, and Piper saw that one of them sensed something in the church, so Mackenzie said that it must be Hive. Piper, May and O'Brien entered the church where they saw the Kree and Hive dueling. Eventually, Hive killed the Kree, so Coulson ordered them to kill Hive. After May and Brady shoots did not work, Piper shot him with her RPG, but Hive immediately healed from the blast. May ordered them to run. They took the injured Mackenzie away from Daisy Johnson and entered the Containment Module and returned to the Playground.
Becoming a Primitive
- "Whens the bloody hanger door going to get closed O'Brien?"
"We've got engineers on it, we had to wait a few days, parts were delayed."
- ―Leo Fitz and O'Brien
Back at the Playground, Brady worked alongside Leo Fitz as they oversaw the arrival of some crates being delivered while ensuring that the captured Hive was ready for transportation inside his Suspension Gel. Once this had been approved, Brady checked on the new crates while Fitz complained about the hanger door still being broken, to which Brady noted the crates were filled with the spare parts they needed. Just as Fitz was walking away however, he noticed something on the crates and ordered Brady to get away. However it was too late as the crates exploded, filling the room with the contaminated Terrigen Mist. Brady was suffocated by the Mist and underwent Terrigenesis, transforming him into one of the hideous Primitives. Losing control of his mind, Brady forced other S.H.I.E.L.D. agents to be transformed and freed Hive before causing chaos around the base.
- Enhanced Strength: As a Primitive, O'Brien possesses adrenaline induced peak human strength and infrared vision.
- S.H.I.E.L.D. (First Incarnation)
- Hive † - Enemy turned Enthraller
- S.H.I.E.L.D. (Second Incarnation) - Allies
In chronological order:
- Agents of S.H.I.E.L.D.