Thor swings, and his opponent doesn't even flinch. That's the most direct moment in the second "Avengers: Doomsday" trailer unveiled live at D23: Chris Hemsworth's Thor raises Stormbreaker and vows to send his enemy "begging hell for mercy," only for Robert Downey Jr.'s Doctor Doom to catch the blow bare-handed and blast Thor back with a green energy beam. No filler, no buildup — the trailer just shows you exactly how much weight this villain carries.

The footage was introduced onstage by Downey Jr., Chris Evans, and Hayley Atwell themselves. It opens with Vanessa Kirby's Sue Storm warning Earth's heroes, before cutting to Doom in his intricately detailed villain armor. Next comes a standoff between Pedro Pascal's Reed Richards and Doom amid the rubble — and before that tension even breaks, Thor is already on the attack. After blocking the blow, Doom summons a full lineup of classic X-Men villains — the Sentinels — and drops the line: "Hell answers to me, for I am Doom."

What really matters here isn't just the spectacle — it's how the trailer lays out the entire scope of the MCU. The Avengers, Fantastic Four, and Thunderbolts are all teaming up against Doom, and beyond that lineup, the Fox-era X-Men cast has now officially been folded into the MCU: Patrick Stewart's Charles Xavier, Ian McKellen's Magneto, James Marsden's Cyclops, Kelsey Grammer's Beast, Rebecca Romijn's Mystique, Alan Cumming's Nightcrawler, and Channing Tatum's Gambit are all in the mix. For anyone who grew up with Fox's X-Men films, seeing these familiar faces show up in the same trailer carries weight all on its own.

"Avengers: Doomsday" is set to hit theaters December 18.