There is 1 Dead Ghost to be found in Cathedral of Dusk. They can be collected during any match. Each Ghost can only be collected once per account.
Ghost 1[edit]
Head for the rock tablet found in the middle of the map inside the Dreadnaught itself. This is by one of the heavy ammo spawns.
Turn and look toward the Dreadnaught wall opposite the tablet. You want to face the same way the tablet is. Next to the coffin prison cell, on its right-hand side, is the Dead Ghost.
