They are pale and slender, they have pointed ears, their lifespan is about a thousand years -- they must be elves.
The Khatrreth were created by the mother goddess. They have perfect pitch, refined artistic sensibilities, and they neither scar, tan, nor wrinkle. Most have blond hair, but a few are redheads. Humans find them difficult to understand, and tend to consider them slightly insane, but still find them attractive. Half-breeds do occur.
Khatrreth live in elaborate 'cities' built out of stone. These cities typically only have a population of 300-500 elves, and seem to be built on the theory that every elf should have his or her own palace to live in. As they reproduce very slowly, and it is rare for a couple to have more than one child every 200 years or so, they prize their children above all else. (They tend to have a soft spot for other people's children as well.)
With a thousand years to devellop their skills, Khatrreth tend to be extrordinary artisans and craftsman. However, patient as they may be compared to humans, the law of diminishing returns eventually catches up with them and to avoid terminal frustration and boredom they tend to reinvent their lives on a regular basis. An elf who spends the first 250 years of his life becoming a master painter, may spend the next 100 becoming a master swordsman, and the next 150 learning engineering, and so forth. They also have a tendency to dramatize every aspect of their lives and although perfectly willing to live as a hermit for a hundred years, they will also spend months or even years rehearsing some collaborative endeavor, in order to awe passing strangers with some amazing pagent or ritual.
While Humans, Giants, and Falran all have to share one language, Khtrreth have three languages all to themselves. Humans refer to these as High Elvish, Low Elvish and Ritual. Low elvish is a more casual variant of High elvish, suitable for outsiders to learn, and for times when you are in a hurry, and for certain forms of poetry. Ritual is a combined gestural/vocal language, almost like a form of dance.
Elves adore anything rare or new, and are addicted to the arts, and most other forms of entertainment. They invented playing cards known as Viashi Cards.