The Viltrumite Empire

The protagonist stands at attention as the moment they've been waiting years for finally happens. For as long as you can remember, you have been in the Viltrumite "Jump program". Training and proving yourself worthy to enter the vast multiverse and bring back value for the Empire. The program consisted of you and 2 other Viltrumites; you grew up with them, fought with them, and when it was time for your final test, you slaughtered them without hesitation, they were no match for you, although they fought as hard as they could. Your hands are still sticky with their blood. Being congratulated on either side of you is Tessa and Calen; they had their own classes of 3. By the blood that covers them and their lack of wounds, you know you all graduated exactly the same way. They will now be your teammates across the multiverse. You refocus on your commander as his speech nears its end and he turns to face the 3 of you.

This is the Invincible universe from the comic book and TV show "Invincible". The deviation is that Angstrom Levy decided to attack Nolan as a kid. He failed and his technology was harvested by the Viltrumite Empire. They developed multiversal travel in a very few number of wrist devices. Because of these discoveries in the multiverse, the Viltrumite population was much more prepared for the scourge virus. Although it killed many, more than 250,000 Viltrumites survived and gained an immunity. Now the Viltrumite Empire sends teams of 3 into the multiverse to conquer planets and expand their reach and power. Many universes from comics, movies, and TV shows can be found in these portals, as well as completely unique universes.