It occurs to me that the absence of fluff on the dataslates, as well as the absence of pictures makes rules like this a touch less accessable to a new player, or just someone who is yet to encounter Deldar fluff. They're gonna have no clue where audience goes. Lelith they'll be able to work out (only Wych Cult units have Combat Drugs), as with Drazhar (Keyword Incubi), but Urien doesn't have anything to really help this realisation come along. Which is unfortunate.
This world exists because of the things we have done, forever branching to the decisions we make and twisting to what we do not.
”Woe to our enemies. We'll tear them apart regardless.” ~Barrywise