Guardsman

Kevin O' Brien

Kevin O' Brien first appeared as himself in Iron Man vol 1 #31 and then first appeared as the Guardsman in Iron Man vol 1 #43. The first Guardsman died in Iron Man vol 1 #46.
 
O' Brien was head of the research department at Stark Industries and a close friend of Tony Stark. O' Brien also knew that Stark was Iron Man. Stark had O' Brien build the Guardsman armor in case of an emergency.
 
A time came when O' Brien put on the Guardsman armor to help Iron Man in battle but a malfunction in the cybernetic circuitry stimulated jealousy and rage in the brain. 
 
The Guardsman behaved in a dangerous and erratic manner. Later, the Guardsman accidentally died when Iron Man attempted to stop his rampage.  

Michael O' Brien

Michael O' Brien first appeared as himself in Iron Man vol 1 #82 and then first appeared as the Guardsman in Iron Man vol 1 #97. 
 
O' Brien, New York City police sargeant, didn't believe that his brother, Kevin, died accidentally in battle with Iron Man. He re-opened the case without authorization believing that there was a cover up of Iron Man's actions. O' Brien managed to get access to the Guardsman armor and put it on hoping to go after Iron Man. 
 
O' Brien was affected by the faulty cybernetic circuitry and as the Guardsman, insane with rage, attempted to kill Iron Man. During the battle, Guardsman was convinced by Iron Man that the armor had a malfunction that caused irrational behavior. Iron Man removed the Guardsman armor from O' Brien and took O' Brien into his custody rather than turn him over to the police. 
 
After two separate battles with Sunfire and the Mandarin, Iron Man revealed that he was Stark to O' Brien. Stark repaired the malfunction in the Guardsman's cybernetic circuirty and the Guardsman hoped to make up for past mistakes. The Guardsman continued to be a reliable ally to Iron Man. 
 
Later, the Guardsman was the security director at Project: Pegasus but  resigned a few years later and came to work for the Avengers as part of the support staff. Years later, O' Brien was contacted by War Machine who was recruiting close friends of Iron Man to fight Ultimo.  

The Vault

 
The Guardsman Armor was later stationed at the Super Villain Peniteniary known as the Vault.

When Obidiah Stane took control of Stark Internation he mass produced the Guardsman armor for the vault.  At the time of the Armor Wars there were 40 armors at the vault.

Due to the mass break out during the "Acts of Vengeance" where the obsolete Guardsmen Mark I armors were replaced by Tony Stark with the Guardsman Mark II.


Guardsman Mark I
30 Minute Self Contained Atmosphere
Cybernetic Interface & Battle Computer
Chemical Fueled Boot Jets
Rechargeable Power Supply
Palm Repulsors

Guardsman Mark II
Short-Range Broadcast Power Batteries
15 Minute Emergency Battery Backup
Cybernetic Interface & Battle Computer
Chemical Fueled Boot Jets
Energy Dampening Field - Protected Armor from a strike that cracked a Mark I's shell.
Palm Repulsors (Enhanced)