Grenzo, Dungeon Warden + The Cauldron of Eternity + Phyrexian Altar + Dark Ritual + Returned Pastcaller

Grenzo, Dungeon Warden

The Cauldron of Eternity

Phyrexian Altar

Dark Ritual

Returned Pastcaller

How it works

1. Cast Dark Ritual by paying , adding .
2. Activate Phyrexian Altar by sacrificing Returned Pastcaller, adding one mana of any color.
3. When Returned Pastcaller dies, The Cauldron of Eternity triggers, putting Returned Pastcaller from your graveyard onto the bottom of your library.
4. Activate Grenzo by paying 2, putting Returned Pastcaller from the bottom of your library into your graveyard, and then putting it onto the battlefield.
5. When Returned Pastcaller 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 clever loop revolves around Grenzo, Dungeon Warden digging from the bottom of your library, a zone neatly managed by The Cauldron of Eternity's replacement effect whenever anything bites the dust. By sacrificing Returned Pastcaller to Phyrexian Altar, you generate the mana needed to fuel Grenzo's ability while triggering The Cauldron of Eternity to tuck Returned Pastcaller right back onto the bottom of your library. As Returned Pastcaller re-enters the battlefield, its triggered ability grabs Dark Ritual back from your graveyard to keep the mana flowing freely. This self-sustaining cycle effortlessly yields infinite colored mana and sacrifice triggers, letting you unleash Grenzo, Dungeon Warden to assemble an entire army from your deck.