In the Marvel Cinematic Universe, when someone wields the Infinity Gauntlet, there is a physical cost. The immense energy coursing through the being causes severe damage, even if the wearer, such as the Hulk or Thanos, is already extraordinarily strong and durable. If the person is of normal strength and durability, like Tony Stark, it will more than likely kill them.
But what if there were a way to wield the Gauntlet without anyone getting hurt? Well, there could be in the form of Life Model Decoys. LMDs are robotic duplicates, constructed to be exact copies down to every detail. So, let's go into detail on the origins and abilities of LMDs in Marvel Comics and the Marvel Cinematic Universe, and then discuss whether or not they would be good substitutes for using the power of the Infinity Gauntlet.
LMDs first appeared in Strange Tales #135 in 1965 in a story called “The Man For The Job!” by Stan Lee and Jack Kirby. In this story, LMDs are used as decoys of Nick Fury during a Hydra attack. They look exactly like the person they are duplicating, having identical irises, fingerprints, speech patterns, body language, and even scent. In addition, they not only have all the original’s memories, but they also mimic their thought patterns enough to fool telepathy. Being androids, they have increased speed, stamina, and durability. On top of that, their skin is made from Epidurium, a metal rarer than Vibranium and Adamantium.
In addition to Nick Fury, LMDs have been used to replace heroes and villains across the Marvel spectrum, and have appeared in multiple alternate universes, including the Ultimate Universe. They have appeared in various other media as well, cartoons, books, and the 1998 TV movie, Nick Fury: Agent of S.H.I.E.L.D. But most importantly, LMDs already have a complicated history in the MCU. The first mention of LMDs in the MCU was a joke by Tony Stark in The Avengers, where, after Agent Coulson arrived at Stark tower to collect him for the Avengers Initiative, Stark claims to be his own LMD. However, LMDs wouldn't make their first actual appearance until the fourth season of Marvel’s Agents of S.H.I.E.L.D.
In the LMD arc, fans learn that Agents Billy and Sam Koenig (both played by Patton Oswalt), were involved in the original LMD program, which failed to produce a working android. In the present day, though, scientist Holden Radcliffe (John Hannah) restarted the LMD program. After giving his digital assistant Aida (Artificially Intelligent Digital Assistant) a body and successfully turning her into a fully-fledged LMD that could pass for human, Radcliffe was forced to use her to save several S.H.I.E.L.D. members stuck between dimensions, as the only way to save them was to read from the Darkhold, a book of cosmic information that would drive any human mad. As an android, she could read from it and survive, theoretically. Not only was she able to do so, but she was able to use the information gained to create a perfect artificial brain, bringing the LMD program to fruition.
Once S.H.I.E.L.D. discovered the truth of the LMD program, it was decided it would continue under the agency. Unbeknownst to them, though, Radcliffe and Aida were working towards their own ends the entire time. Eventually, the evil duo was defeated by S.H.I.E.L.D. with the help of Ghost Rider. Later in the series, at the end of Season 6, LMDs returned when Agent Coulson was brought back as a much more advanced version using Chronicom technology after his death.
With all that in mind, it's fair to debate whether LMDs could handle the power of the Infinity Gauntlet. On the one hand, Aida’s successful reading of the Darkhold would suggest that they could, given its nature as another supremely powerful cosmic artifact. However, even if they could survive, it’s not clear whether they could even use it in the first place. It's unclear if the Gauntlet is aware of the nature of its user, and if a sentient, organic being must be the one to wield it. If that's the case, then LMDs wouldn’t be in consideration. However, if the only qualification to use the glove is to be sentient, this scenario could be an ideal one.
It's possible that had Tony Stark had the time to gain access to an LMD before the events of Avengers: Endgame, he wouldn't have had to sacrifice himself by using the power of the Infinity Gauntlet. Hopefully, the next time Earth's Mightiest heroes find themselves in a situation similar to the one at the end of Endgame, they'll use this more creative solution instead of having to say goodbye to one of their own.