Brace yourself: Avengers: Doomsday trailer has fans sure an MCU hero’s done for
Avengers: Doomsday’s trailer has fans convinced one MCU hero is marked for death — and you won’t like who they’ve got in their sights.
Marvel have dropped the first trailer for Avengers: Doomsday, due in cinemas on 18 December 2026, and let’s just say things have got a bit dark for Loki fans. The film’s being directed by the Russo brothers, with a genuinely sprawling cast and, for once, Robert Downey Jr. not as Tony Stark but as the new big bad, Doctor Doom. The speculation is already wild, and to be fair, the footage doesn’t help—if you thought Marvel might go easy on the Norse god of mischief this time, you may want to brace yourself.
Loki pops up in the Doomsday trailer and, according to a popular fan theory, Doctor Doom is set to kill him off—potentially for good this time.
Just how bad is it for Loki?
The trailer itself doesn’t come straight out and announce Loki’s death, but it’s done enough to get fans hypothesising all kinds of tragic ends. Thor’s reaction to Doom in the footage is... let’s call it unfiltered rage, and it’s this moment that’s fanning the flames online. One commentator was blunt enough to spell it out: Doom 'will literally rip his heart out.' No mucking about.
Thor, by the way, hasn’t exactly been having a smooth time in the MCU. Between losing an eye, his arm, both parents, his entire home, Jane getting killed, and now possibly watching his brother die again, fans are starting to wonder if he’s secretly auditioning for the title of “saddest superhero in mainstream cinema.”
The theories don’t stop with just a grisly death for Loki. One idea doing the rounds has Doom stealing Loki’s 'God of Stories' power; another suggests Mobius is on hand to help a battered but not entirely gone Loki plan his revenge from the sidelines. There’s even a scenario where Steve Rogers tries to break the news gently to Thor, only for Thor to stumble across Loki’s shredded body with a piece of Doom’s armour lying there like some kind of sick taunt. In this version, Doom’s not just causing carnage—he’s absorbed Loki’s multiverse-level abilities, so Thor is basically up against Doom plus everything Loki ever was. Not a cheerful prospect.
Who’s actually in this thing?
‘Ensemble cast’ doesn’t begin to cover it. First up, Chris Hemsworth is back as Thor, and Tom Hiddleston returns as Loki. Anthony Mackie is on board as Captain America, alongside Paul Rudd (Ant-Man), Letitia Wright (Shuri/Black Panther), Florence Pugh (Yelena Belova), Wyatt Russell (U.S. Agent), Simu Liu (Shang-Chi), Lewis Pullman (Sentry), Danny Ramirez (Falcon), David Harbour (Red Guardian), Winston Duke (M’Baku), and Hannah John-Kamen (Ghost).
It gets even busier with Channing Tatum popping up as Gambit, and a proper fan-service roll call from the X-Men side—Patrick Stewart, Ian McKellen, James Marsden, Alan Cumming, Kelsey Grammer, and Rebecca Romijn are all in. The Fantastic Four: First Steps lot are also crossing over, so expect Pedro Pascal, Vanessa Kirby, Joseph Quinn, and Ebon Moss-Bachrach to also show up. Chris Evans will put in a return as Steve Rogers. The headline grabber, though, is Robert Downey Jr. – not as the beloved Iron Man, but as the terrifying Doctor Doom.