[@Billsomething]
Well, the Imperium just sort of died, so let's skip that one.

The Alliance of Conquerors is an alliance of conquerors. It's in the name. A group of high-powered villains banded together, and are currently leading a massive army to conquer everything they can.

The Goa'Uld are a powerful intergalactic empire that recently gained interdimensional travel capabilities. They're also attempting to conquer this world, but they're doing it for Ba'al, a being they worship as a God.

The inkvasion group is kind of a small comedy relief group composed of two squid girls and a magical interdimensional esper with plans of ending all of reality. So yeah, standard fare. Also, beware Ika Musume, she be OP as shit.

Lastly there's the Dark Outliners, who have mysterious plans based on the even more mysterious plans of their mysterious leader, the Envisioning One. They recruit individuals for their cause by playing to their sense of morality, and offering to return them to their home dimension in return for their services. While they don't seem to be malicious, they're certainly dangerous, and definitely devious, and most assuredly.... mysterious.