Underbridge Warlock (YWOE-008) [Alchemy: Wilds of Eldraine]

Deathtouch
When Underbridge Warlock enters, you get a one-time boon with "At the beginning of your end step, if three or more creatures died this turn, each opponent loses 5 life and you gain 5 life."
At the beginning of your end step, if you have a boon, you mill three cards, draw a card, and lose 2 life.