From TheWarWiki

Do you doubt that we are the true race of elves, my young slave? Do you doubt that we shall one day reclaim the homeland your loathsome kin occupy? Then consider the Dark Art - a power so awesome that only the Druchii have mastered it. While your insignificant wizards poke and prod at the forces of the universe, filled with fear and trepidation, we can bend those forces to our will with a mere thought. Khaine has judged us worthy - us and no others! Think on this, and know that soon, it will be the Druchii who rule the island Kingdom of Ulthuan.

Akrana, a Sorceress of the Dark Elves, speaking to one of her High Elf slaves.

Examine a "Worn Cage" at (54k, 3.8k), amidst other cages holding Mirelen Devotees captive. Be wary of a patrolling Champion Dark Elf in the area.