Blacklight is a location in Skyrim: Dragonborn
It is the capital of Morrowind, ever since Mournhold was sacked by the Argonians
Raven Rock still gets the occasional supply ship and visitors from there.
The Argonians invaded Morrowind quite a while ago. They cut a bloody swath across most of the southern region of Morrowind. Nobody seems certain why it happened... an attempt of expansion, revenge for the enslavement of their people or perhaps both. Whatever the case may be, thousands of Dunmer needlessly lost their lives and many more were exiled from their homeland.