Runner Customization in Marathon

Marathon does not use a traditional face/body character creator -- each Runner is a pre-designed character, and customization instead means unlocking and equipping Shell skins, which are strictly visual cosmetics with no effect on abilities, weapons, or gameplay performance.

The main unlock method is extracting successfully while using a specific faction Sponsored Kit (free or paid) -- after a successful exfil, go to the Codex, open Sponsored Kits for that faction, and select the class that used the kit to claim its style.

Additional shell styles come through Codex challenges (including faction-specific styles like the Disciples of Arachne look) and the seasonal Battle Pass, which Bungie has expanded more than once after community feedback that the initial cosmetic offering felt thin for its price.

Once unlocked, a shell skin stays permanently available for that Runner going forward -- there is no need to re-earn it each season.

See the full data: Marathon Classes