Rakdos, the Muscle + Priest of Gix + Haunted Crossroads + Umori, the Collector + Yahenni, Undying Partisan

Rakdos, the Muscle

Priest of Gix

Haunted Crossroads

Umori, the Collector

Yahenni, Undying Partisan

How it works

1. Activate Yahenni by sacrificing Priest of Gix.
2. When Priest of Gix dies, Rakdos triggers.
3. Holding priority, activate Haunted Crossroads by paying , putting Priest of Gix from your graveyard onto the top of your library.
4. Resolve the Rakdos trigger, causing you to exile the top three cards of your library with the ability to play them until your next end step.
5. Resolve the Yahenni ability from step 1.
6. Cast Priest of Gix from exile by paying 2.
7. When Priest of Gix enters the battlefield, it triggers, adding .
8. Repeat.

This clever loop puts your graveyard to work by turning Priest of Gix into a self-sustaining engine. Yahenni, Undying Partisan acts as the sacrificial outlet, feeding the priest to the graveyard while Haunted Crossroads immediately fishes it back to the top of your library for a single black mana. Meanwhile, Rakdos, the Muscle triggers off the sacrifice to exile the top of your library—and thanks to Umori, the Collector lowering the artifact or creature costs (depending on how your deck is built), you can easily recast the priest using the mana it generates upon entering the battlefield.