Chainer, Dementia Master + K'rrik, Son of Yawgmoth + Gray Merchant of Asphodel + Sadistic Hypnotist

Chainer, Dementia Master

K'rrik, Son of Yawgmoth

Gray Merchant of Asphodel

Sadistic Hypnotist

How it works

1. Activate Sadistic Hypnotist by sacrificing Gray Merchant, causing target player to discard two cards.
2. Activate Chainer by paying nine life, returning Gray Merchant from your graveyard to the battlefield as a Nightmare in addition to its other creature types.
3. Gray Merchant enters the battlefield, causing each opponent to lose life equal to your devotion to black and causing you to gain life equal to the amount of life lost this way.
4. Repeat.

This loop relies on Chainer, Dementia Master to continuously reanimate Gray Merchant of Asphodel from the graveyard, turning it into a black Nightmare so Chainer can track it. K'rrik, Son of Yawgmoth makes this reanimation economically viable by letting you trade your life total for Chainer's steep black mana costs, while the massive life drain and gain from Gray Merchant's entry replenishes that life buffer with interest. Finally, Sadistic Hypnotist provides the mandatory sacrifice outlet to send the Merchant back to the graveyard to restart the cycle, while simultaneously stripping your opponents of their hands.