Oathsworn Vampire + Phyrexian Altar + Honest Rutstein

Oathsworn Vampire

Phyrexian Altar

Honest Rutstein

How it works

1. Activate Phyrexian Altar by sacrificing Oathsworn Vampire, adding .
2. Cast Oathsworn Vampire from your graveyard by paying .
3. Repeat.

This loop relies on Phyrexian Altar to constantly recycle your creatures while generating the exact black mana needed to recast them. When you cast Oathsworn Vampire from your graveyard, its ability to be cast from the yard is unlocked because sacrificing it to the Altar satisfies the life-gain condition if your life total changed, or you can leverage Honest Rutstein to reduce its casting cost to just {B}. Honest Rutstein also provides a valuable enters-the-battlefield trigger to recur creature cards when initially played, and its static cost reduction makes the entire looping engine cheap and efficient to sustain.