The Deep Blue Sea actor revealed that his malevolent god of mischief character will go up against all the major cast of the film, including Thor (Chris Hemsworth), Iron Man (Robert Downey Jr) and Captain America (Chris Evans).
"The fun thing about Loki is that he goes one-on-one with every single Avenger," Hiddleston told Total Film.
"Loki has become so menacing that they all have to team up and overcome their differences to stop him.
"I think I can dismiss the mere mortals, so Captain America may be a super soldier but he's still a man and he's up against Loki, who's a God. I think Iron Man's blasters hurt a bit.
"But I think it comes down to his thunderous brother. No-one is harder to fight than his brother because there's all that angst within him. Thor still comes out on top."
Hiddleston praised the cast and crew of the Marvel Studios movie.
"It's been the most incredible privilege to work with my own heroes," he said. "The greatest superheroes in the world played by some of the greatest actors in the world."
Hiddleston recently revealed that Loki will be "more gangster" in the ensemble movie.
> 'Thor' sequel will visit other worlds, says Marvel president
Watch the teaser for the Captain America post-credits scene and a first look at The Avengers below: