War Machine

: "138 combat missions. That's how many I've flown, Tony. Every one of them could've been my last, but I flew 'em. Because the fight needed to be fought."
: ―James Rhodes to Tony Stark[src]
Colonel James Rupert "Rhodey" Rhodes is a former officer in the United States Air Force and liaison between the Department of Acquisitions and Stark Industries, where he became close friends with Tony Stark. When Stark had been kidnapped by the Ten Rings, Rhodes personally led a mission to rescue his best friend. However, upon their return, Rhodes saw Stark moving away from developing his weapons for the military and soon discovered that he was instead focusing on becoming a hero known as Iron Man. Despite all of his fears for his friend's safety, Rhodes still joined Iron Man in bringing down Obadiah Stane's schemes, while trying to keep Stark's secrets, only for Stark to reveal them to the media himself.
With Iron Man's identity known, Rhodes found himself under pressure from the United States Congress and the military to take possession of the armor for himself, something that he was against. However, as Stark's reckless behavior got even worse, Rhodes had no choice but to take the Mark II before handing it over to the military, with Justin Hammer upgrading it with his new weapons to rebrand Rhodes as War Machine. However, just when War Machine was being presented to the world, Ivan Vanko returned and attacked the Stark Expo with an army of Hammer Drones, as War Machine teamed up with Iron Man to bring him down, resulting in Rhodes keeping the armor for himself, despite Stark's continued objections.
In response to the Chitauri Invasion, Rhodes took on the identity of the Iron Patriot and worked directly for President Matthew Ellis. When a terrorist called the Mandarin was claiming responsibility for a string of domestic terrorist attacks, Rhodes was dispatched to hunt him down. However, Rhodes discovered that the Mandarin was a ruse created by Aldrich Killian by hiring actor Trevor Slattery to portray the role. Killian managed to capture Rhodes, steal the Iron Patriot Armor and use it to kidnap President Ellis. Rhodes managed to free himself and teamed up with Stark to defeat Killian's army before saving President Ellis.
Reverting back to the War Machine name, Rhodes continued serving his country by assisting the Avengers in the Battle of Sokovia, ensuring that as many Sokovians were evacuated before Ultron could cause mass extinction. Following the battle, Rhodes became an official member of the Avengers. However, Rhodes soon found himself in conflict with the team as the debate over the Sokovia Accords led to Captain America and Iron Man disagreeing, with War Machine siding with the government. As the conflict worsened, War Machine clashed with Captain America's allies, only for War Machine to be disabled as he had been inadvertently shot out of the sky by Vision.
Having been given leg braces by Tony Stark to help him walk again, Rhodes became disillusioned by the government and decided to disobey Thaddeus Ross' orders and instead assisted Steve Rogers as they had learned of the impending Thanos' quest. Once they traveled to Wakanda in order to protect the Mind Stone, War Machine fought alongside his allies in their attempts to hold back the Black Order. However, as Thanos arrived, War Machine and the others were unable to defeat him, resulting in the Snap.
Determined to undo Thanos' actions, War Machine joined the Avengers on a mission to Thanos' Garden, ending in Thor beheading the Mad Titan. Five years later, the Avengers learned to travel through time and initiated a Time Heist, where War Machine joined Nebula on a mission to obtain the Power Stone from Morag in 2014. Succeeding in the mission, the Avengers resurrected the victims of the Snap, before being attacked by an alternate Thanos and his entire army. War Machine then joined his fellow heroes in battling Thanos until Stark sacrificed his life to finally eliminate Thanos, as Rhodes stayed by his best friend's side during his final moments before attending his funeral.