An image of Grom Hellscream will manifest before players on live servers who acquired 
Gorehowl, Might of the Warchief from Dawn of the Infinite!
When you possess the new Gorehowl transmogged or in your inventory, Grom will briefly materialize, kneeling and saluting towards you before vanishing.
Grom Appears if you have the New Gorehowl
byu/Doomhammer24 inwow