Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters the battlefield, each opponent loses
X life where X is equal to your devotion to black.
You gain life equal to the life lost this way.
My Lord Nur al-Din, have you not heard the saying
He who spends without reckoning, becomes poor
without knowing it? My lord, this enormous expense
and lavish giving will erode even mountains.
—The Arabian Nights