Although Sargeras was skeptical about the combat strength of the Four Horsemen of the Apocalypse, he didn't say anything. In his opinion, having helpers was definitely better than having no helpers.
Sargeras still had a group of servants under him, and even his apprentice, Aggramar, could respond to his summons. But in the Void World, the environment limited his performance, and he couldn't summon anyone at all. Now that he saw that Roy had found a group of helpers for him, and from the sound of it, these helpers came from another world, it made him attach greater importance to Roy again.
In the few seconds that Sargeras was thinking, the Four Horsemen completed their observation of the surroundings. The existence of the Void Sun shocked them all.
