So I saw the cinematic trailer, and it looks awesome btw. But one thing intrigued me, why is Illidan staring at that skull? Who is it, and why is he holding onto it?
I am of the opinion he is merely reflecting or reminiscing on the act of consuming Gul'dan's skull. The skull in the cinematic was Orcish in nature, if I recall correctly. Could've resembled Gul'dan's, hence what would cause Illidan to think of it.