Minor Factions is a feature added to Sins of a Solar Empire Rebellion by the DLC of the same name. It adds a variety of small, single planet factions at the start of the game that can either be persuaded to join your Empire or be conquered. When a player allies with a minor faction, it will fight for them, give some of its income as tribute, and most importantly will grant the player access to several unique abilities.
Unlike regular militia, minor factions begin the game with their planets already upgraded and a decent self defense force. They will eventually rebuild any ships or structures that are destroyed at their planet.
Minor factions have a chance to spawn at most unowned colonizeable worlds at the start of the game. In general however they will not spawn too close to a player's homeworld. They can also be turned off completely in the game setup menu.
Allying with a Minor Faction
Players use Envoy Cruisers to get Minor Faction's to join their Empire. When an envoy cruiser uses its Goodwill ability on a neutral minor faction, the minor faction will join the owner's Empire. The Envoy must stay at the planet and constantly use the Goodwill ability to keep the Minor Faction friendly; the minor faction will revert to a neutral state if the envoy leaves or stops using the Goodwill ability. If another player has captured a minor faction, it's envoy cruiser must be destroyed, incapacitated, or forced to retreat to revert the minor faction to neutral, which will let a different player capture the Minor Faction with their own Envoy.
Conquering a Minor Factio
A neutral or enemy controlled Minor Faction can be conquered like any other world. If a minor faction world is completed bombed out, the minor faction at that world is permanently removed from the game and its unique abilities will no longer be available for any player.
List of Minor Factions