Now if there's one thing every comic-book fan loves, it's a good villain. Whether it's a giant, world-devouring galactic being, or a small-town thug trying to make good, they're often the difference between a good superhero story, and a great one - and Marvel does them better than most.
The thing is, though, between the small horde of awesome villains we've already seen in the Marvel Universe - I'm looking at you, Loki and Thanos - and the inevitably large number set to arrive during the recently announced Phase 3, there aren't too many major Marvel villains left on the comic-book shelf for the powers-that-be behind the MCU to adapt for the screen.
As it turns out, though, there are still a couple of awesome villains who we aren't likely to see until at least Phase 4. Here, then, are five awesome bad guys to look forward to...by about 2020...
Kang the Conqueror
One of the most legendary villains in Avengers history, Kang is a time-travelling historian from the 30th century, who has, through the years, adopted several different personas in his bid to dominate the timeline.
Mostly, though, he was a complex, thoughtful and persistent opponent of the Avengers - and would make for a natural 'big bad' were we to see a more time-travel themed Phase 4.
Most Likely Movie Appearance: Guardians of the Galaxy 3, Followed by appearances in Doctor Strange 2 and Avengers 4.
The super-intelligent, mutagenically-altered creature known as M.O.D.O.K was originally designed for computing by the terrorist organization - and long-time Captain America foes - AIM. However, he overthrew his programming, and became M.O.D.O.K. - a 'Mental Organism Designed Only for Killing'.
With his long-standing history with Captain America, M.O.D.O.K. (along with AIM) could well make for a perfect first opponent for Bucky Barnes, should he find himself the new Captain America in Phase 4. Could we even discover that AIM had something to do with Bucky's conditioning into The Winter Soldier?
Most Likely Movie Appearance: Captain America 4
And, of course, there's:
Fin Fang Foom
Now, let's be honest, the long-time Iron Man and Thor-opposing giant green dragon Fin Fang Foom is about as out there a super-villain as we're ever likely to see in the MCU - but that might just make him a perfect villain for Phase 4.
After all, if Marvel has to reboot Iron Man, they'd have the opportunity to take the new Tony Stark in a very different direction to the one we've seen so far. Could he end up fighting the greatest dragon the Marvel universe has ever seen - or would Fangy make a more natural opponent for, say, Captain Marvel?
Most Likely Movie Appearance: Captain Marvel 2
After someone a little more...small-scale, though? Try:
Originally from Kansas City, Missouri, David Cannon discovered at a young age that he had the ability to move at super-speeds, while taking a form not unlike a whirlwind - which he promptly took advantage of to become a jewel thief.
Soon, though, he found himself up against Ant-Man and The Wasp - and became a long-standing opponent of the pair, as well as a member of the super-villain team The Masters of Evil.
Most Likely Movie Appearance: Ant-Man 2
And, of course, there's a villain we almost - but not quite - saw:
Now, we have technically already seen The Mandarin in the MCU - he was, after all, one of the principal villains in Iron Man 3.
That being said, the version we saw on screen was a far-cry from the legendary villain from Iron Man's past - and the Marvel One Shot All Hail the King might just have revealed that there's a whole other Mandarin out there, just waiting for his chance on the big screen...
Most Likely Movie Appearance: Iron Man 4