Kabal
A Kabal is a sort of clan or House of Dark Eldar, with a big heap of organized crime family thrown in.
Origin
There used to be proper royal houses in Commorragh, dating back to the Eldar Empire, and persisting even after the Fall. They operated cautiously, raiding Imperial worlds infrequently, so as to avoid attracting the ire of the Imperium. Asdrubael Vect didn't much like their aristocratic/nepotistic ways (having been a slave before clawing his way into a position of relative power), so he arranged their downfall by intentionally raiding the Imperium, eventually luring the Salamanders into Commorragh to wreck things. Since he was expecting them, his Kabal of the Black Heart stayed intact, and cut-throat (figuratively and literally), meritocratic Kabals like his became the ruling bodies of the Dark City.
Organization
Each Kabal is headed by an Archon. Unlike most mob bosses, Archons are often in the trenches, getting into the thickest part of the raids, as hanging back is a sign of weakness. Under him are the Dracon, the officers of the Kabal and leaders of the deadliest squads, who often plot against their Archon. Then come Kabalite Warriors, who are themselves segregated into the "Trueborn", those born from an actual mother and father, and the mass-produced vat-grown "half-born". At the very bottom are the slaves who do all the menial work and, when they aren't good for anything else, get tortured to feed the souls of the Kabalites with their pain.
Kabals often work in parallel with other Dark Eldar organizations. Most Archons sign a contract with a coven of Haemonculi, promising new victims and working material (often the two are the same) in return for access to resurrection chambers and the assistance of whatever horrors the coven has at its disposal. Wych cults, Reavers, and other unsavories looking for glory may tag along (or be paid to come along) on a raid.
A Dark Eldar who stands out from the crowd can earn prestige and leadership, but the ambitious can also move up in life by killing their immediate superiors and taking their place. This is not seen as problematic by Commorragh society -- in their eyes, a leader who cannot stop his subordinates from killing him obviously isn't much of a leader. On the other hand, he's also considered not much of a leader if no-one wants to kill him.
Tabletop
In game terms, one's choice of Kabal only has an effect on the colors and decorations of the vehicles and armor.
Notable Kabals
- Kabal of the Black Heart, the most powerful Kabal in Commorragh, headed by Asdrubael Vect.
- Kabal of the Poisoned Tongue, headed by Vect's former consort Lady Aurelia Malys
- Kabal of the Wraithkind
Homebrew Kabals
- Dark Eldar Kabal Creation Tables, a set of fluff tables for generating your own Kabal.
- The Enshrouded, a /tg/ 40,000 Kabal composed mostly of Haemonculi and their covens.