The Marvel Cinematic Universe has completed Phase Four without a new major antagonist to replace Thanos, but when Phase Five with Ant-Man and the Wasp: Quantumania arrives, Kang the Conqueror—will become the next major antagonist of the franchise. And who is he?
Kang the Conqueror, played by Jonathan Majors, is a looming menace to the whole multiverse, as shown in the Ant-Man and the Wasp movie trailers. Quantumania is a thriving town in the Microverse inside the Quantum Realm.
You see, this isn’t Jonathan Majors’ first appearance in the MCU; he made his debut in Loki, but not as Kang the Conqueror, but as He Who Remains, Kang’s variant. Jonathan Majors ruled the “Sacred Timeline” for so long that he established the Time Variance Authority to stop variants like Kang.
In any case, Sylvie murdered him because she had a big resentment against him, but that action caused millions of parallel worlds to split out, one of which has Kang the Conqueror. He Who Remains could only do so much, but there’s little doubt that Kang would be safest in the Quantum Realm.
He might have properly hidden there for generations since the time and space there function differently. As for how he got there, that remains a mystery, but considering that Avengers: The Kang Dynasty is in the works, Kang the Conqueror is already being positioned as the next, and deadlier, Thanos of the Marvel Cinematic Universe.
Kang is one of the bad guys that went back in time in the comics. He goes by the name Nathaniel Reeds and is a researcher from the 31st century who is also a relative of Reed Richards, thus it makes sense to introduce the Fantastic Four as well.
Nathaniel became infatuated with history, and thanks to Doctor Doom, who is also making his way to the MCU, Nathaniel was able to travel to any period he desired, even becoming a Pharaoh, where he encountered En Sabah Nur/Apocalypse.
Nathaniel recreated himself as Kang the Conqueror and established his temporal dominion by conquering universes across time. While he lacks superhuman abilities, his intelligence is his most powerful weapon.
With the entrance of Kang the Conqueror in Ant-Man and the Wasp: Quantumania, it is quite probable that Kang will eventually reveal himself to everyone in the picture; yet, while it will introduce him and his dynasty, he may not be the true evil of the film.