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Illegitimate Investigation[]

Michael O'Brien was a sergeant of the NYPD, and the brother of engineer Kevin O'Brien, who became the Guardsman and accidentally died while fighting Iron Man (who was in secret Michael's boss Anthony Stark). Although the police investigation exonerated Iron Man, and a fellow officer who was involved the investigation tried to convince Michael it was an accident,[2] he believed it was a cover up.

He confronted Stark at a charity party for the Iron Man Foundation, accusing him of having killed Kevin. Stark offered to talk it out, but O'Brien refused.[3] He also attempted to question Iron Man (secretly Happy Hogan who had filled in for his employer at a charity function) when he was in a hospital after a fight with Red Ghost's Super Apes.[4] He also approached Roxanne Gilbert[5][6] and continued to harass Stark himself.[7] He hired a criminal P.I. whom he had caught in the act[8] to infiltrate Stark's Long Island plant.[9] He was infuriated when the P.I. could not turn up any evidence to support his theory.[10]

Becoming Guardsman[]

During his illegitimate investigation, Michael found the Guardsman Armor and donning it,[11] decided to use it to defeat Iron Man and take him to justice. However, the Guardsman Armor was defective and affected the brain, stimulating the areas that caused aggression, jealousy and hate (This had happened to Kevin too). Michael went crazy and changed his mind: He had to kill Iron Man.

Iron Man fought Michael and discovered the flaw in the armor. Iron Man then captured Michael himself, instead of pressing charges, because he wanted to convince O'Brien of his innocence.

During this time, a saboteur had stolen most of Iron Man's armors, and Stark was working on a new design, but unfortunately the armor itself was not finished - it was too hot to wear it. At that moment, Japanese mutant Sunfire attacked, and Tony Stark was unable to use any of his traditional armors. Thus, he had to use the Guardsman armor. O'Brien witnessed Stark's heroics saving lives at a monitor, understanding that Stark was risking a heart attack, not to speak of brain damage.

O'Brien decided that he was wrong about Stark and put on Iron Man (now cold) armor to fight Sunfire. Due to this, O'Brien was mistaken as the true Iron Man by Iron Man's enemy Mandarin, who kidnapped O'Brien and took him to Chicago.

Stark found an old Iron Man armor ignored by the saboteur and went to rescue O'Brien. During the rescue, Stark revealed to O'Brien his true identity and then fought the Mandarin. After this, O'Brien returned to New York with the Guardsman Armor. Stark then fixed the flaw in the armor so that it could be used, and offered the armor to O'Brien. O'Brien then decided to use the armor to avenge his brother's bad actions and his own.

Eventually, Stark International was taken over by criminal Midas. O'Brien, now the Guardsman, joined some of Iron Man's friends and allies to fight Midas. O'Brien was turned into gold by Midas' power, but eventually recovered.

Project P.E.G.A.S.U.S.[]

O'Brien left the police and was interviewed to become head of security of Project P.E.G.A.S.U.S., the main energetic research post of the government, after the dismissal of their previous head of security, Quasar. With good references from Stark, O'Brien got the job.

Michael O'Brien (Earth-616) from Iron Man Vol 1 300

As Iron Man against Ultimo

O'Brien's Guardsman armor was damaged in a battle with the Lava Men, but it was repaired at the expense of his employers. O'Brien has been working full-time at Pegasus since being hired.

The Vault[]

Eventually, most of the tasks using super-villains at Pegasus were transferred to the Vault. O'Brien was also transferred and named security head of the Vault. The security agents also use copies of the Guardsman Armor, manufactured by Obadiah Stane under Stark's patent.

O'Brien also suited up with Bethany Cabe, Eddie March, Happy Hogan, and Force to face Ultimo when asked by War Machine.

Avengers Support Crew[]

Without his armor, O'Brien was affiliated with Captain America and the Avengers as part of the team's support staff.


Power Grid[13]
:Category:Power Grid/Fighting Skills/Some Training:Category:Power Grid/Energy Projection/Single Type: Medium Range:Category:Power Grid/Energy Projection/None:Category:Power Grid/Durability/Bulletproof:Category:Power Grid/Durability/Normal:Category:Power Grid/Speed/Superhuman:Category:Power Grid/Speed/Normal:Category:Power Grid/Strength/Superhuman (25-75 ton):Category:Power Grid/Strength/Normal:Category:Power Grid/Intelligence/Normal


  • Investigation: O'Brien is an exceptional detective.[12]
  • Firearms: O'Brien has good marksman skills.[12]
  • Hand-to-hand Combatant: O'Brien has good fighting skills.[12]


O'Brien's Guardsman Armor was created by Tony Stark and is infused with Stark technology. The Guardsman Armor is inherently inferior to Stark's Iron Man Armor MK IV as well as all other versions of Iron Man armor.



  • Guardsman Armor: O'Brien wore the Guardsman Armor who gave his several superhuman abilities.[12]
    • Superhuman Durability: The armor is made of steel alloy and is extremely durable.[12]
    • Superhuman Strength: The armor enhances is strength to the point where he could lift 40 tons.[12]
    • Flight: The armor featured jet boots that allowed him to fly at 135 mph.[12]
    • Energy Projection: The armor was equipped with several energy projectile weapons including repulsor rays.[12]


Repulsor blasters in the armor; police issue handgun


Jet boots in the armor.


  • O'Brien is of direct Irish descent.

See Also

Links and References