Usually dwelling in isolated regions of space, these areas naturally attract renegades, exiles, and mercenaries. Without the guidance of the Emperor, this drudge of humanity often fall to the powers of Chaos. However many do not, instead opting for a life of plunder. Hiding away on fringe worlds, moons, or in asteroid belts these men form pirate fleets. Their ranks are filled with deserters from the Imperial Guard and Imperial Navy as well as those fleeing from the Adeptus Arbites. Many are also anti-Imperial insurgents, who see themselves as freedom fighters against the tyranny of the Adeptus Terra.
Pirate bases act as safe havens for every criminal, miscreant, heretic, and rebel throughout the Imperium. Such bases are a constant bane to the Imperium, often serving as epicenters for raiding outposts and isolated colonies. However most pirates survive by living off the plunder acquired through raiding Imperial Merchant Fleets. When faced with the firepower of the Imperial Navy however most Pirates will opt to flee, for they lack the heavy firepower or capital ships of the Imperial Fleet. However due to their hit-and-run attacks and guerrilla tactics, Pirates are usually able to stay one step ahead of the Imperial Navy.
Such is the level of piracy in the Imperium's space lanes that one of the prime duties of the Imperial Navy is to hunt down pirate bases and keep shipping lanes safe for Merchant ships. It is important for the Imperial Navy to destroy pirate bases early, for they have been known to grow exponentially as a successful pirate fleet gains more followers, glory, and plunder. Eventually an unchecked pirate fleet could even check Imperial rule at the System level.
Pirate leaders find it difficult to control their wayward forces, and thus a fleet will often be made up of many different factions and individual warlords looking out for themselves as opposed to combining efforts for the common good. As such it's little surprise that infighting and backstabbing are common among pirate fleets.
Pirates prefer to operate in 'Wolf Packs', small squadrons of swift craft which will launch an ambush against unprotected targets. Wolf Packs often operate in areas where the Imperial Navy is already embattled against heretics or xenos, forcing the Imperium to divert ships to stop their raiding. Usually when faced with Imperial warships, pirate Wolf Packs prefer to scatter and fight another day.
Pirates will rarely strike or operate in deep space, such regions lack plunder and are often extremely hazardous. At the same time they will rarely raid a world or the space around it, where orbital defenses and Defense Monitors can quickly respond to their threats. Instead, pirates prefer to strike in shipping lanes and sparsely inhabited regions of Imperial space.
Commonly encountered Pirate ships include:
- Iconoclast Class Destroyer
- Idolator Class Raider
- Sword Class Frigate
- Firestorm Class Frigate
- Cobra Class Destroyer
- Defense Monitors
- Escort Carrier
- Fire Ship
- Dark Eldar
- Eldar Corsairs
- Ork Freebooterz
- Chaos Space Marine Warbands (mostly notably the Red Corsairs)