The Cultist Cell can choose to move to a neighboring Region or remain in place.
The Cultist Cell joins a Dreadhorde located in the same Region and is permanently removed from the map. The Dreadhorde recovers an amount of Health that results in its Effective Combat Strength increasing by the Effective Combat Strength of the Cultist Cell. If the Dreadhorde is already at full Health, its Base Combat Strength is increased by the Effective Combat Strength of the Cultist Cell.