Add a new rule called Vampire Lords:

Each Vampire Lord has a Puissance, which is a publicly tracked non-negative integer that defaults to 10. Power Actions always require that their Cost be paid from the Puissance of the Vampire Lord carrying it out.

Each Vampire Lord has an Allegiance, which is secretly tracked and which defaults to Loyal.

Add a new rule to the ruleset, called Lair Actions:

Exploring a Room is a Power Action with a cost of 5. The Vampire Lord carrying it out may select a room and set it to Explored, giving it a name and a description, and an effect of “none”.