Details from the new movie are slowly coming out as we get closer to the Avengers 4's release date. The Avengers: Infinity War had the first leaks because of the toys. The Avengers 4 was the new victim of these toys that we learned some of the characters and the flow of the story.
As you may recall, the new armor of Thor and Rocket Racoon, was announced. It was revealed that these were some kind of armor they would wear in Quantum Realm. Behind this leaked armor photo there is information about the new enemy. Also, it shows that this enemy will be different than Thanos.
Avengers 4 toy says there will be a new enemy.
The post behind the Avengers 4 toy is as follows;
“The Asgardian Thor wields the mighty Stormbreaker in his battle against new foes. Rocket teams up with a new crew to guard the galaxy from an even greater threat.”
According to this information, our only enemy is not Thanos. In this film, after Thanos's actions, he can awaken a stronger enemy. Perhaps even an enemy that could push Thanos to cooperate with the Avengers. But we have two names that come to our minds, the Skrulls, which we will meet them with the Captain Marvel movie, and the other is Galactus. Galactus feels the first change in the universe. In addition, Galactus is a very important detail in the Avengers Infinity War comic book. Although Fox has the rights of Galactus right now, the deal between Marvel and Fox most likely is going to be completed when the movie is out.