There are 8 human factions in the Shallow Space universe:

The 3 core empire factions with overall control of the majority of humanity.
The 3 mighty corporations, nipping at the emperors heels for dominance
The 2 subversive authorities living outside of the core worlds of Shallow Space in the fringe colonies nibbling at the edges of the Imperium.

Some of the factions are further split into subordinate authorities or companies, some with Elite units and/or special abilities.

Find out about the next revealed core empire faction the 'Terran Confederate Navy' over on the blog...

[Abbreviated: TCN] The Terran Confederation Navy was formed in response to the discovery of the Pleiades Corporation, descendants of the presumed lost worldship UES Halifax. When the Pleiades Corporation refused to enter the Terran Empire, Emperor Christian decided to force the issue. He issued the construction of a military fleet to occupy the Pleiades system....