A guide explains where to find the hidden skulls and terminal in the “Pillar of Autumn” mission of Halo: Campaign Evolved. Collecting them changes campaign gameplay or unlocks lore, and finding all four earns the “Clean Sweep” achievement.

– Speed Limit skull: At the mission’s start, reach the right-hand ledge via the cryo chambers; it disables sprint.
– Magnified skull: In armoury B02, jump onto the third group of weapon racks; it gives assault rifles 60-round magazines.
– Perspective skull: After meeting Captain Keyes, return to the bridge and drop beneath the marines at the helm; it switches to a third-person camera.
– Approach terminal: After the ventilation route, enter room B04 immediately to the left; it provides lore.