Travel to Blackrock Spire and collect 20 Black Dragonspawn Eyes. Return to Myranda the Hag when the task is complete.
So the [race] wishes to become one of the Black Flight, eh?
The creation of the illusion you require is trivial, but the components required for the divination are quite difficult to obtain. Rexxar and the Warchief have entrusted you with this mission, so Myranda must assume you as capable.
Travel to the upper citadel of Blackrock Spire and slay enough of the black dragonspawn to fill up one of your packs with their eyes.
Return to Myranda when you have gathered enough of the reagent.