Factions are one of the main progression systems in Marathon. They are tied to contracts and upgrades, which makes them a big part of how your runs start feeling better over time. As you work through faction contracts, Marathon improves your baseline power with things like Runner Shell upgrades, stronger starting loadouts, expanded vault space, and better wares in the Armory.
Right now, Marathon has six factions: CyberAcme, NuCaloric, Traxus, MIDA, Arachne, and Sekiguchi Genetics. What makes the faction system important is that it is not just there for extra objectives. Factions are how Marathon turns individual runs into bigger seasonal progress. You take on contracts, build reputation, unlock upgrade nodes, and open up better tools for future runs.
The contracts system is pretty straightforward once it clicks. Marathon uses Liaison contracts to unlock new factions, then gives you Priority contracts and Standard contracts to keep building reputation with them. Standard contracts are repeatable, priority contracts are the larger progression bonus, and you can only have one active contract at a time. If you are playing with a crew, contract progress is shared, which helps move things along faster.
Each faction also leans into a different part of the sandbox. CyberAcme is tied more closely to starter utility and vault growth, NuCaloric leans into survival and recovery, Traxus is closely connected to weapons and mods, MIDA focuses more on utility and equipment, Arachne has a stronger PvP focus, and Sekiguchi Genetics is tied more closely to Runner shells, cores, and biomata-related power.
One important thing to know is that faction progression is seasonal. Marathon resets faction progression, contract progression, gear, and player level at the start of a new season, but the system does not fully send you back to square one because Liaison contract progression carries over.