Yarus, Roar of the Old Gods + Master of the Veil + Altar of Dementia

Yarus, Roar of the Old Gods

Master of the Veil

Altar of Dementia

How it works

1. Activate Altar of Dementia by sacrificing Master of the Veil.
2. When Master of the Veil dies, Yarus' second ability triggers, returning Master of the Veil from your graveyard to the battlefield face down, then turning it face up.
3. Master of the Veil triggers, turning itself face down.
4. Resolve the Altar of Dementia ability, causing target player to mill cards equal to Master of the Veil's power.
5. Repeat.

This clever loop turns the graveyard into a revolving door for your morph creatures, fueled by Yarus, Roar of the Old Gods granting both haste and a resurrection trick whenever a face-down creature dies. By sacrificing Master of the Veil to Altar of Dementia, you trigger Yarus to bring it right back face down and immediately flip it face up, which in turn triggers its own ability to turn itself face down again. Because Master of the Veil is continually cycling between the battlefield and the graveyard while repeating its own morph-flipping loop, Altar of Dementia can be activated over and over to mill your opponent out completely.