A millionaire socialite and genius inventor who doubles as the high-tech armored adventurer Iron Man, Tony Stark has been a vital part of the Avengers in both his identities. 

     As Iron Man, he helped found the team and continues to participate in the group today. As Tony Stark, he donated his family home to serve as the group's original headquarters (Avengers Mansion), invented or serviced much of the team's specialized equipment, financed the team's early operations, and later established the Maria Stark Foundation to fund the Avengers in perpetuity. As such, Stark has been one of the team's most invaluable assets, though he has also been one of their most troubled and sometimes disruptive members over the years.

     Stark went on indefinite leave again while struggling to control his alcoholism, during which time he allowed his friend and confidant Jim Rhodes to replace him, both as Iron Man and as a member of the Avengers. Stark eventually returned to sobriety and to active Avengers duty as a member of the team's new western roster, but he was later expelled after he waged a vigilante campaign to seek and destroy all duplications of his Iron Man armor technology. These "Armor Wars" concluded with Stark faking Iron Man's death in battle, and then returning to activity under the pretense of having hired a new Iron Man to replace the original (until recently, Stark had pretended that Iron Man was merely one of his employees, supposedly Stark's personal bodyguard).

     Stark rejoined the Avengers as the "new" Iron Man, but most of his teammates were not fooled and he soon revealed his true identity to them. The other Avengers forgave the deception, and even elected him to a short-lived stint as chairman of the team's western roster; however, he continued to be an increasingly disruptive presence within the Avengers' ranks, causing a deep ethical rift and lasting tension in the group during the "Galactic Storm" mission, when he led a team of renegade Avengers in trying to execute the Supreme Intelligence for its crimes of interplanetary genocide. Shortly thereafter, Stark faked his own death again (this time as Tony Stark) when he had himself placed in suspended animation while his physicians worked to cure him of a degenerative neurological condition. During his absence, he was again replaced as Iron Man by Rhodes. Stark was eventually revived and cured, but the revelation of his latest hoax was the final straw that alienated many of the Avengers, even Rhodes.

     Iron Man continued to serve with the group occasionally as a reservist of sorts, and disrupted the team once more when he attended a joint membership hearing to decide the fate of the group's faltering West Coast division. Bitterly condemning the Avengers' lack of support for their western roster, Iron Man led most of its remaining active members in resigning from the Avengers altogether and forming a new team called Force Works, financed by Tony Stark. Soon, though, Iron Man left that group as well, due to his frequently insubordinate attitude toward team leader Scarlet Witch.

     During their conflict with the Immortus-controlled Iron Man, the Avengers had gone back in time to find a new Iron Man of their own, one untouched by the mental manipulations of "Kang", and recruited a teenage Tony Stark from an alternate timeline. With the Avengers' help, the teenage Stark was outfitted and trained as a new Iron Man, helping to resolve the "Crossing" crisis and later moving into Avengers Mansion, aiding the team in their adventures as an honorary member of sorts. Teen Tony's career as "Iron Boy" proved short-lived, however, when he was one of the many Avengers lost and presumed dead in the battle with the supremely powerful psychic monster known as Onslaught. In actuality, they all survived, but were displaced into an alternate reality unwittingly created by the near-omnipotent mutant child Franklin Richards when he subconsciously used his powers to save the heroes. When the Avengers finally returned to Earth, it was the benevolent adult Tony Stark of old who returned with them rather than the teenage version. Apparently, Richards instinctively tried to restore Iron Man to normal when he brought him back to his proper universe, merging the late adult Tony with teen Tony and producing an Iron Man who seems to be the original adult Iron Man in both mind and body

     Cleared of any wrongdoing in the Crossing case, Iron Man participated in the post-Onslaught reorganization of the Avengers and has been a mostly active member since then, though he has occasionally taken further leaves of absence for health problems or other personal reasons. He served briefly as deputy leader under chairman Captain America before stepping down from the post due to time constraints, and was replaced in that capacity by Scarlet Witch. Stark has rebuilt his friendships with most of his Avengers teammates, including Rhodes. Stark also recently took the radical step of revealing his long-secret role as Iron Man to the general public.

     There have also been two significant new developments in terms of Stark's Avengers associations: honorary Avengers member Jocasta, originally a sentient robot, became a disembodied computer intelligence and served as Tony Stark's personal assistant after he freed her from enslavement at the hands of criminal technologist Madame Menace (she has since left Stark's service after procuring a new android body of her own); and the Avengers recruited the Jack of Hearts, a costumed adventurer whom Iron Man had mentored for a time when Jack was starting out as a superhero. Powerful and well-intentioned but physically and emotionally unstable, Jack literally blew himself up despite the efforts of Stark and others to offer him guidance.

     When the insane Scarlet Witch killed several of her fellow Avengers and destroyed Avengers Mansion, the team disbanded--partly because they felt too emotionally traumatized to continue, but also because Iron Man claimed that he and the Maria Stark Foundation lacked sufficient funds to properly rebuild the team's operations. Later, when Captain America and Iron Man were among the heroes who helped battle the mass breakout at the Raft super-prison, Captain America invited Iron Man and most of the other heroes involved to join him in forming a new Avengers team. Iron Man reluctantly accepted, and even donated the use of his Stark Tower skyscraper as the group's new headquarters, in addition to providing other elements of fiscal and technological support. Like Avengers Mansion, the new Stark Tower headquarters is staffed by Edwin Jarvis, formerly the Stark family's servant, who has been the Avengers' butler since the team's founding.

Iron Man (James "Rhodey" Rhodes)
Identity assumed for two extended periods by James Rhodes when he twice took over the Iron Man role from his friend and employer, Tony Stark, the original Iron Man. Rhodes later adopted an armored identity of his own as War Machine, though he abandoned that guise, too. Rhodes had declared himself retired from adventuring, but later organized a vigilante group known as The Crew, and he served with the Avengers as both Iron Man and War Machine in the past. Rhodes was the fourth of the various "substitutes" who have assumed Stark's Iron Man guise over the years, but he was the first and only alternate Iron Man to play the role on a long-term basis, and the first to join the Avengers (the only other Iron Man who ever joined the Avengers apart from Stark and Rhodes was the teenage Tony Stark of an alternate timeline who briefly served as an honorary Avenger). More recently, Rhodes has served as part of a team of pilots controlling the government's latest giant Sentinel robots.

Iron Man (the teenaged Tony Stark of an alternate timeline)
Former honorary member of the Avengers, now non-existent. When Immortus (disguised as Kang) mind-controlled Avengers founder Iron Man into turning against the Avengers during the crisis known as "The Crossing", the Avengers went back in time to find a new Iron Man of their own, one untouched by the supposedly longtime mental manipulations of "Kang". To this end, they recruited a teenage Tony Stark from an alternate timeline. With the Avengers' help, the teenage Stark was outfitted and trained as a new Iron Man, helping to resolve the "Crossing" crisis and later moving into Avengers Mansion, aiding the team in their adventures as an honorary member of sorts. Teen Tony's Iron Man career proved short-lived, however, when he was one of the many Avengers lost and presumed dead in the battle with the supremely powerful psychic monster known as Onslaught. In actuality, they all survived, but were displaced into an alternate reality unwittingly created by the near-omnipotent mutant child Franklin Richards when he subconsciously used his powers to save the heroes. When the Avengers finally returned to Earth, it was the benevolent adult Tony Stark of old who returned with them rather than the teenage version. Apparently, Richards instinctively tried to restore Iron Man to normal when he brought him back to his proper universe, merging the late adult Tony with teen Tony and producing an Iron Man who seems to be the original adult Iron Man in both mind and body. Teen Tony and the body of the slain adult Tony both disappeared without a trace, apparently absorbed into or otherwise eliminated by the resurrection of the adult Tony Stark.