Formed by those that abandoned the modern Shetou to return to more traditionalist ideals, led by Yasrena Val'Hari formed by the primary houses Beldoban, Jaal'darya, Vloz'Khress and Sarghess. Kar'Soluth is a lot less tolerant of non-drow races and see the drow as the true masters of civilization. Their politics operate in a very similar fashion to the old Shetou ways with all the violence for council power intact. Karsoluth came about from people with a general distaste for the way Shetou was running things and the prominence of the "eastern houses" along with the works of Laesaaria Val'Hari. While normally they might have just tried to kill off those opposing elements we happen to be privvy to knowledge of the Phantoms conspiracy that indicates this was definitely done by Yasrena for ulterior motives than just distaste of the other races.
Despite the dramatic exit from Shetou's official empire, Kar'Soluth hasn't really done much else. It seems they expected House Sharen to go with them, but when that didn't happen they were left sitting around without the naval superiority they expected to have over the original Shetou and have had to reconvene.
House Beldoban
Representing themselves with the color black to extremes. They like dark colors and have a culture of making themselves unseen, uninteresting, and unfeeling. They are very isolationist and their mindset is to endure in neutrality to outlast the chaos of everyone else. The modern era forced them to acknowledge the changing world and its interconnected nature to remain as a council house. They have survived by being willing to make logical sacrifices where necessary and always pursue their decisions as numerically as possible. This makes it somewhat hard to trick them into mistakes or bad decisions due to their hyper-logical approach. Currently they are on the verge of losing their status mostly due to lack of loyalty from citizens and their struggle to continually grow with the expansion of available space and population in the modern world.
House Jaal'darya
Regarded as slightly crazy, the Jaal'darya are pioneers of science in all its forms though they specialize in medical affairs. The best cybernetics, surgeries, and vaccines come from the Jaal'darya though historically they have been known to go to any extremes necessary for their experiments. They are not tightly aligned with any other house and due to the importance of their scientific progress the empire has a silent agreement not to mess with them. Not to mention they have been known to work with diseases quite often. In the old times they were somewhat disliked for their tendency to take everything other houses owned when their expertise was desperately needed, but the modern economy has supported the masters of medicine so well that they have become a little less vicious in their business dealings. A lot of conspiracy theories point to the Jaal'darya as culprits behind something nefarious or other, though to be fair history shows they were behind quite a lot of conspiracies and medical disasters.
House Sarghess
A military house that rose to power on the backs of commoners. Originally founded by citizens of the empire who felt the great houses had too much power and were too superior to the common man that they depended on for their economies. It started as something of a lower class revolt but in time somehow became a house of its own, filled with the common man. In time their leaders and their children became venerated for leading them out of the streets and into power and it wound up as just another great house in time. It still holds onto its roots with a generally rough and militant culture, its matriarch is descended from Quaintana and considered a hero in their own right. The nobles of Sarghess don't live as affluently as those in other houses but are still much better off then the commoners it once rose up from.