You will need to clear three Strongholds in Diablo 4‘s Kehjistan region: Alcarnus, Altar of Ruin, and Omaths Redoubt. Each of these Strongholds has its own challenges and bosses, but once you’ve cleared them all, you will gain access to an Altar of Lilith. Once you’ve cleared each Stronghold, you will gain access to a new public area and any vendors, side-quests, or Waypoints it contains.