Trickery, Blood - Lawful Evil
Nylva (Neel-vah) is a goddess of Trickery and Blood, and the patron of all dark elves. The high and wood elves view her as an abomination, one of the first elves born of Vilsya who ascended to godhood through dark, twisted rites now lost to time and memory (though desperately sought after by the misguided few who aspire to become gods themselves). After her ascension, she was met in battle by Haelmir and others of the pantheon, and cast out, banished to the Shadowfel. Upon her banishment, she began to corrupt many of the early elves, giving them dark gifts and twisting them in her image. They were left cruel and heartless, and their society lacks the trappings of such things as "love" and "mercy".
To the dark elves, she was the first, the mother of all elves, and the one who ultimately led to the creation of Vilsya. She is Haelmir's mortal enemy and they have prophesied the day she rises from the Shadowfel to slay Haelmir and enslave Vilsya before ruling over the rest of the elven gods with an iron fist. Unlike the other gods, Vilsya does not accept any male clerics or priests, and encourages a survival of the fittest, ruthless sort of matriarchal pecking order among her followers - who are almost entirely drow.
It is rare, and nearly unheard of, to find shrines or temples built in Nylva's honor, and indeed worship of her is usually done in secret by cults and people terrified to admit they are her followers for fear of persecution. This is not a prejudice that is unearned... Nylva's cults have been behind catastrophic uses of dark magic, and once even killed a former High Mother of Elanshir before sacrificing her unborn child to the dark goddes in a ritual that nearly killed the elder tree found in the High Mother's grove. In depictions, Nylva is a strong dark elf woman with stunning, but cruel features, and usually carries a whip.