haha yes, Illidan justs picking up that something is fucky and then oh is that the scent of demons over there? Excuse him. He's got things to murder over THAT way.

Illidan would only pick up on it while he's in another body, any ability not in use he wouldn't be able to see coherently. Like, he won't be able to tell Mukuro can use illusions just by seeing him, but he'd uh.. I guess see him/his general power in grape flavor, if that makes sense.