While this noble family is truly ancient and has had influence in the region for more than two thousand years - even outside of the Sh'areen Caliphate, they have never attempted to lay claim to any large areas. They are mostly content with control over the valley where most of them live. Their true power lies in how they keep a presence everywhere. They trade in information and advice. The guardian spirit of House Nyelandir is a is a noble siamese cat. It is normally portrayed wearing gold and silver adornments.
The Qel'tath is Samanthis Nyelandir. Her partner, Faylanthi Nyelandir, was originally born to House Redhok. They have three children, all elves but with a significant amount of human blood in them. This isn't appreciated by everyone within House Nyelandir, but they are bound enough by tradition that no one has dared bring this up in an official capacity. Of special note is Samanthis uncle, Remberthan Nyelandir, is the current diplomat sent to House Seelon and the Jewel Palace. He is both a trusted ally of the other house, and assumed to be a spy. While the current Qel'tath of the powerful noble house, Anhara Seelon, seems very happy with this political dance of give and take, her cousin Ahneid is much less fond it. And he's next in line to lead House Seelon.
House Nyelandir portray themselves as benevolent guides to those who would listen. And while they are sometimes viewed with suspicion as others wonder what exactly they are guiding the world towards, most of what they achieve seems to be for the betterment of all. Of course, not all choices can be equally beneficial to everyone. There are envoys and diplomats representing House Nyeladir at the court of nearly every other noble house within many hundred kilometres. This includes not just House Seelon, but also House Silvertree and the Chorlonni family .
While politics and information is really the main trade of the Nyelandir family, there are several rare fruits and crops that grow in the caverns of Silvar Canyon. It might not be an oasis, but there is water seeping up from underground that carries unusual substances from the Underdark. This sometimes gives the produce here take un unusual properties.
The exact founding of Silvar Canyon isn't known, but it has likely been around for at least tens of thousands of years, and House Nyelandir has been important for a significant amount of that time. The settlement was once the centre of a small kingdom of its own but was defeated by an Orc invasion in 2300 BSR. House Nyelandir took charge in repairing not just their own home, but also the relationships with surrounding rulers. By seeming weak, the family could make sure other others took risks for them. When House Seelon established control over the larger region, House Nyelandir struck some very favourable agreements with them, securing some independence for the Silvar Canyon. They maintained this even during the more tumultuous years of the War of the Dunes, and remained neutral. They managed to sell this to the Sh'areen Caliphate as remaining loyal.