I am throwing this out to the masses in the hopes that I get some good suggestions (please?). My Sunday game is currently fourteenth level (4E D&D), and they are at Starfel, the former capitol of the tiefling nation. I say former because around seventy-five years ago a flaming rock fell from the heavens and smashed the capitol of Cael'doresh into the ground. Upon their arrival, Jinx (a tiefling) sought the ambassador she had rescued from the city of Galen. The ambassador, Venomia, asks Jinx and the pc's in general, if they would be interested in visiting an archaeological dig site.
My plan is at some point in checking out this dig site, they will encounter a race from the the far in the the Cael'doresh nation's past, a boogie man if you will. In my mind, I visualize a shadowy being that, when hit drops easily, but comes back with an edge against it's attacker. I do not want a long list of powers, ideally I will use a minion for the initial creature, then switch to one of several specific creations.
I could go resistances for the different damage types, but I would rather have something special. This is where you come in, do not be shy, if you have any suggestions please let me know, knowledge of 4E is not necessary. All ideas are welcome and I am looking forward to seeing what you guys can come up with.