The Skull is in the first open area with the Wraiths. You can kill off stuff, just don't kill the Wraiths. (When you kill them the skull disappears). The skull is on the storage tank on the far side of the field from where you entered. Getting it can be challenging. Either use grenades to help boost your jumping or pull up a Wart Hog to the front of the tank and jump up that way. If you didn't kill the wraiths the skull is right on top.
Thanks! :)
DaoraScale2112 3 years ago