Syr Konrad, the Grim (207) [Modern Horizons 3 Commander]

Whenever another creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves your graveyard, Syr Konrad deals 1 damage to each opponent. {1}{B}: Each player mills a card. (They each put the top card of their library into their graveyard.)