Bloodlord of Asphodel

Constellation - Whenever Bloodlord of Asphodel or another enchantment enters the battlefield under your control, each opponent loses 1 life.
At the beginning of your endstep, if an opponent lost life this turn, you may pay X life where X is the amount of life they lost this turn. If you do, return a creature card in your graveyard to your hand unless they pay X life also.