MCU: 10 Insanely-Powerful Villains Who Could Be The New Thanos
10. The Maker
So, Reed Richards went crazy and tried to kill everyone. You hear that? That void of nothingness? That's the shattering quiet of no one being shocked.
Reed Richards has always been a stick in the mud, morally compromised fop who is utterly convinced he's better than everybody else. Difference is that 616 Reed has been through enough humbling experiences to temper his ego enough so that he doesn't go completely over to the dark side. Ultimate Reed Richards, not so much.
Anyway, convinced his universe is a bore, Reed - now calling himself "The Maker" decides to leave to find a more interesting universe... after destroying this one. Because he'd be a rather poor villain if his motivation stopped at needing a vacation. We have this guy to thank for rebooting the entire Marvel universe and merging it with the Ultimate universe, so yeah, kind of a big deal.
With the MCU now introducing the multiverse, as well as finally getting the rights to the Fantastic Four, it would definitely be cool to see a villain who completely embodies the idea of different universes and experiences.