Menace
Greven gets +X/+0, where X is the amount of life you've lost this turn.
Whenever Greven attacks, you may sacrifice another creature. If you do, you draw cards equal to that creature's power and you lose life equal to that creature's toughness.
(23/08/2019)
Greven checks for how much life you lost, not how much your life total has changed. If you lost 4 life but also gained 6 life, you still lost 4 life and Greven gets +4/+0.
(23/08/2019)
The sacrificed creature's power and toughness are determined by its last known information before it left the battlefield.
(23/08/2019)
You sacrifice a creature (or choose not to), draw cards, and lose life all while Greven's triggered ability is resolving. Nothing can happen in between, and no player may choose to take actions.
(23/08/2019)
A player loses life if they're dealt damage or if they pay life.
