Heroes are cross-faction characters introduced gradually: they become available as soon as they are deployed and progress by completing missions they are compatible with. Each has two accessory slots.
The Faction > Heroes page lists only heroes that are actually available, without showing future slots. A hero can be free or assigned to a mission. When assigned, a hero is unavailable, but a faction change does not interrupt a mission that has already started.
Each hero has their own list of compatible missions, bonuses, and experience rules. Mission selection displays only compatible heroes. For Mira Venn, the experience gained per hour on Excavations is detailed in Heroes on Excavation Missions. Naël Soryn receives 400 XP at the end of each Pillar Hack lasting 30 minutes, even if he is detected or no movement is observed; the Codex increases this gain based on its level. Mira and Naël progress through 20 levels, up to 112 650 XP.
An accessory you own can be equipped on only one hero at a time. Accessories can only be equipped or unequipped while the hero is free, including after a faction change. Accessories and hero progression remain specific to each player. The accessory catalog and transfer rules are described in Hero Accessories.