Loki did a great job of building a mystery around who was really in charge of the Time Variance Authority, and that only deepened once we learned the Time-Keepers weren't real.
For a moment, it appeared as if Miss Minutes might be the show's big bad, though we'd soon learn that a Kang the Conqueror Variant, He Who Remains, was really pulling the strings. Loki's villain was a mix between that character and Immortus, though we'd need about a dozen articles to fully explain their complicated comic book history!
All you really need to know is that Immortus has a very distinct appearance in the comic books, and that very nearly made it into the Disney+ series. As you can see below (via ComicBook.com), Marvel Studios considered including his familiar headpiece, bringing He Who Remains more in line with how Immortus looks on the page.
This was far from essential, of course, as the Kang Variant still looked very much like his counterpart in the Marvel Universe. Still, it would have been a nice touch, even for just a single scene.
We also get a glimpse at how Kang might have looked prior to Jonathan Majors being cast, though Marvel Studios couldn't have found a better actor for the role. That's evident from what we saw in the Ant-Man and The Wasp: Quantumania trailer, and with a Multiversal War on the horizon, the actor will get the chance to really stretch himself in the MCU.
The question is, will Earth-616's heroes be able to finally put an end to Kang or will one of his Variants once again end up back at the end of time guarding a new Sacred Timeline? That remains to be seen, especially as we've only just started exploring this Multiverse Saga.
Season 2 of Loki is set to premiere on Disney+ next year.