The Forsworn(Without an E to avoid confusion with a certain group of World Eaters) are a Group of Dark Eldar who have a massive Craftworld called The Reach, with a Population of 230,000,000. They have produced Millions of Vehicles, and are the fourth force involved in the Anthrus conflict, they often like to cause petty incidents in the system, such as murdering random people in worlds then running off like nothing happened. The Forsworn are massive rivals with the Redwall system and want to start a massive war with them.
The Forsworn are also known for their plundering of other planets outside the Anthrus system, and with the Plunder have developed new Technology. Including Hovertanks and much more.
The Forsworn are also looking to build a second Craftworld. And Therefore are planning to Plunder Redwall.