Grenzo, Dungeon Warden + The Cauldron of Eternity + Phyrexian Altar + Dark Ritual + Eternal Witness

Grenzo, Dungeon Warden

The Cauldron of Eternity

Phyrexian Altar

Dark Ritual

Eternal Witness

How it works

1. Cast Dark Ritual by paying , adding .
2. Activate Phyrexian Altar by sacrificing Eternal Witness, adding one mana of any color.
3. When Eternal Witness dies, The Cauldron of Eternity triggers, putting Eternal Witness from your graveyard onto the bottom of your library.
4. Activate Grenzo by paying 2, putting Eternal Witness from the bottom of your library into your graveyard, and then putting it onto the battlefield.
5. When Eternal Witness enters the battlefield, it triggers, returning Dark Ritual from your graveyard to your hand.
6. Repeat.
7. Once you have infinite mana, you may activate Grenzo's ability any number of times.

This intricate loop turns Grenzo, Dungeon Warden into a reliable reanimation engine by manipulating the bottom of your library. The Cauldron of Eternity plays a pivotal role behind the scenes, ensuring that whenever a creature dies—like when you feed it to Phyrexian Altar for mana—it goes straight to the bottom of your library rather than staying in the graveyard, perfectly positioned for Grenzo to pull it back out. As Eternal Witness cycles in and out of play, its entry trigger continuously returns Dark Ritual to your hand, fueling the mana required to keep the loop going while netting infinite resources.