The Marvel Cinematic Universe has grown and "branched" in many directions, especially with the onset of the Multiverse. As a result, new characters like Ms. Marvel and new versions of classic characters, like Loki, have shown that anything is possible in this universe, no matter the reality. Most importantly, with a world of vampires coexisting with street-level heroes in a universe of Celestials, it's even easier to bring in heroes and villains that would've seemed impossible in earlier phases. This has become even more evident in the realm of villains and who has and hasn't been introduced.
Source：https://www.cbr.com/mcu-big-villain-arcade-incredibles/
