To activate the last ability, you may tap any untapped Vampires you control, including ones you havenâ€™t controlled continuously since the beginning of your most recent turn. (Note that tapping the creature doesnâ€™t use [the tap symbol].)
Once you announce that youâ€™re activating Deathless Ancientâ€™s last ability, no player may take other actions until the abilityâ€™s been paid for. Notably, players canâ€™t try to stop the ability by tapping or removing Vampires you control.
Deathless Ancientâ€™s last ability can be activated only while itâ€™s in your graveyard.