Keys

Keys are one of those item types in Marathon that can feel confusing at first, because they are not all used the same way. Some keys are there for loot access, some open specific rooms or facilities, and others are tied to the UESC Marathon and Cryo Archive map.

The clearest key type right now is the Lockbox Key. It opens Lockboxes, and each locked chest uses one key per chest. Lockbox rooms are marked with red flares on the roof, and the reward pool can include things like valuables, salvage, credits, Cores, and consumables. That makes Lockbox Keys one of the more straightforward ways to turn a run into stronger loot, as long as you stay alive long enough to use them.

Marathon also has named access keys tied to specific places. Current examples include Airfield Building, Maintenance Pump, and Welcome Center. These are not generic chest keys. They are tied to secure locations, with keys like Airfield Building and Welcome Center linked to Outpost, while Maintenance Pump is tied to Dire Marsh.

Then there is the more mysterious side of the system: Marathon C.01 through Marathon C.06. These keys are tied to the UESC Marathon and Cryo Archive map, and their item text suggests encrypted access data connected to that endgame part of Marathon.