Once you hit a milestone in your adventure, you’ll be able to choose from three factions: the Marauders, the Syndicate, and the Covenant.
The Marauders, as the name may imply, are militaristic. The Syndicate are more secretive and chase enlightment. The Covenant are more fanatical and want to rid the world of heretics. The team expands on PvP here,
“When we made the decision to remove always-on open-world full-loot PvP from New World, it was not a decision to remove Player vs. Player (PvP) combat from the game. In fact, we wanted to focus it, to create stakes that everyone in Aeternum could invest in, even if they aren’t directly interested in PvP themselves.”
As such, these factions form the basis for PvP. The aim will be, of course, to help your faction establish dominance in the world. You do this by controlling territories. You’ll run missions for your faction and gain rewards. Missions include defeating creatures, crafting supplies, or stockpiling resources.
The team also notes on Twitter that accepting a PvP mission will auto-flag you for PvP. If you unflag yourself, you’ll abandon that mission. Dying will also cause you to fail in which case you’ll have to accept another mission.