Grenzo, Dungeon Warden + The Cauldron of Eternity + Phyrexian Altar + Dark Ritual + Possessed Skaab

5-card combo · UBR

Verdict

Yes — this 5-card loop generates infinite colored mana and functions as a creature-based storm engine in any Grixis shell that runs Grenzo as commander.

Cards required: 5
Cheapest stack total: $2.05
Color identity: UBR
Popularity: 0 decks
Format: Commander

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Possessed Skaab returns Dark Ritual to hand on each enter-the-battlefield trigger, while The Cauldron of Eternity routes it back to the bottom of the library so Grenzo can flip it again for 2. Each loop costs 2 mana and nets back the Dark Ritual, meaning the first real loop goes positive and every subsequent activation is free, generating infinite storm count, death triggers, and colored mana simultaneously.

Recipe

How it works

Prerequisites

Grenzo has power 2 or greater.

Steps

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

Result

Infinite colored mana; Infinite death triggers; Infinite ETB; Infinite LTB; Infinite magecraft triggers; Infinite sacrifice triggers; Infinite storm count; Put a selection of creature cards from your library onto the battlefield

Variations

Cheaper, tighter, alternate lines

Myr Retriever or Archaeomancer can substitute for Possessed Skaab if the recursion target is adjusted to any instant or artifact — the critical role is returning Dark Ritual on ETB. The combo assembles via Buried Alive putting Possessed Skaab into the graveyard to prime The Cauldron of Eternity before the loop starts; once mana goes infinite, activate Grenzo to pull every creature in the library and close with a free win condition already in the bin.