Rakdos, the Muscle + Priest of Gix + Haunted Crossroads + Umbral Collar Zealot + Thunderscape Familiar

Rakdos, the Muscle

Priest of Gix

Haunted Crossroads

Umbral Collar Zealot

Thunderscape Familiar

How it works

1. Activate Umbral Collar Zealot 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 Umbral Collar Zealot ability from step 1.
6. Cast Priest of Gix from exile by paying at most 2.
7. When Priest of Gix enters the battlefield, it triggers, adding .
8. Repeat.

This clever loop centers around Rakdos, the Muscle, who turns every creature sacrifice into exiled library depth you can freely cast using any color of mana. To fuel this engine, Umbral Collar Zealot provides the necessary sacrifice outlet, while Thunderscape Familiar reduces the cost of your black spells so that Priest of Gix generates more mana than it takes to recast. Whenever Priest of Gix enters the battlefield to supply that vital burst of black mana, you can respond to Rakdos's exile trigger by using Haunted Crossroads to loop the Priest right back onto the top of your library. Finally, the surveil from Umbral Collar Zealot clears away any unwanted draws, letting you continuously replay Priest of Gix to exile your entire library and generate an infinite storm count.