Here's one of the finished objective markers.
While I am trying to keep the full story of the army a surprise until it is fully written, I do want to say that the world which the Dark Eldar are invading drew their attention not only by the existence of the Hippodrome.
Something else drew them, a suffering which permeated space and time itself.
This world is very much like the Rome of Nero, with witches, mutant and heretics being thrown to the wolves, quite literally, in the Hippodrome. Mass executions were popular entertainment on this world.
The ruler of this world even begins to have fantasies that he is the Emperor of Man.
In the end, the 'nobelmen' and women of this society, who always owned slaves, will be themselves enslaved by the Dark Eldar. The oppressors will now be locked in the same cages as those whom they oppressed.
It's gonna be fun!