Tom Hiddleston's Loki was arguably the breakout character of Marvel's first Avengers movie. With the sly charm that Hiddleston brought to the role, Thor's adopted brother became a seeming rarity in the Marvel Cinematic Universe: a villain who is fun to watch.
Marvel is certainly aware of his charm, and is taking advantage of it by having the trickster god run for president of the United States. However, that does not mean he will always be around in the MCU. In fact, a recent comment from Hiddleston suggests that Loki's big screen days beyond Thor: Ragnarok may be numbered.
In a recent interview on Earwolf's Happy Sad Confused podcast (as reported by CBM), Hiddleston talked about a number of topics, including his turn as Hank Williams in the biopic I Saw the Light and his work on the upcoming Kong: Skull Island. He also delved into what is in store for Loki in the MCU, both in Thor: Ragnarok and (maybe) beyond:
"[Thor: Ragnarok] is coming around. I saw Chris Hemsworth in Australia. He lives about an hour away from where we were shooting Kong: Skull Island, and he was full of beans about Thor 3. Thor 3 will be cool because I’ve not done it for four years. I love working with Chris [Hemsworth]. This will be my last time out of the gate."
When asked if that meant that Loki would not be returning for The Avengers: Infinity War Part One after his appearance in the next Thor movie, Hiddleston backtracked a little:
"I don’t know! Honestly, I don’t know. They haven’t got their ducks in a row yet. They make it up as they go along."
Given how far out Marvel has planned the MCU, Hiddleston's comment that they make it up as they go along seems questionable. No doubt the actors are kept in the dark about possible returns, though, both to avoid spoilers and as a tactic for negotiating salaries. After all, if Hiddleston knew that there was, for instance, an important plot point involving his character in Infinity War Part Two but his contract is only through Thor 3, then that puts him in a much better bargaining position than he would have otherwise.
Or perhaps Marvel does indeed have only the thinnest outline of what is to come, and it is left up to individual directors and screenwriters to fill in the blanks. After all, Thor 3 director Taika Waititi has said that Marvel has "no rules" when it comes to making movies in the MCU, although their parting of ways with Edgar Wright during the making of Ant-Man casts some doubt on that claim as well. Either way, discarding a character as beloved as Loki (or even recasting him in the wake of Hiddleston's departure) seems like it would be a wasted opportunity, and he would certainly make an interesting player in the universe-spanning Infinity War series. For now, however, fans will just have to wait to find out if he survives his next fraternal throw-down.
Captain America: Civil War will release on May 6, 2016, followed by Doctor Strange – November 4, 2016; Guardians of the Galaxy 2 – May 5, 2017; Spider-Man – July 7, 2017; Thor: Ragnarok – November 3, 2017; Black Panther – February 16, 2018; The Avengers: Infinity War Part One – May 4, 2018; Ant-Man and the Wasp – July 6, 2018; Captain Marvel – March 8, 2019; The Avengers: Infinity War Part Two – May 3, 2019; Inhumans – July 12, 2019; and as-yet untitled Marvel movies on May 1, July 10 and November 6, 2020.