Kenrith, the Returned King + Phyrexian Altar + Agatha of the Vile Cauldron

Kenrith, the Returned King

Phyrexian Altar

Agatha of the Vile Cauldron

How it works

1. Activate Phyrexian Altar by sacrificing another nontoken creature, adding .
2. Activate Kenrith's fifth ability by paying due to Agatha of the Vile Cauldron, putting the creature card onto the battlefield from your graveyard.
3. Repeat.

By leveraging Agatha of the Vile Cauldron's static cost reduction, the steep mana price for Kenrith, the Returned King's reanimation ability is slashed down to a single black mana. This creates a brilliant and efficient loop when paired with Phyrexian Altar, allowing you to sacrifice the reanimated creature to generate the exact black mana needed to bring it right back from the graveyard. The result is a continuous, self-sustaining cycle that endlessly repeats the creature's entry and exit from the battlefield, generating an infinite stream of sacrifices and death triggers.