Rakdos, the Muscle + Priest of Gix + Haunted Crossroads + Grimgrin, Corpse-Born + Cloud Key

Rakdos, the Muscle

Priest of Gix

Haunted Crossroads

Grimgrin, Corpse-Born

Cloud Key

How it works

1. Activate Grimgrin 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 Grimgrin 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 fascinating loop turns a modest black ritualist into an infinite engine by leveraging cost reduction and graveyard manipulation. With Cloud Key naming creatures, the mana-positive entry of Priest of Gix generates a surplus of black mana every time it cycles through exile. Haunted Crossroads ensures the Priest is immediately retrievable from your graveyard to the top of your library, where Rakdos, the Muscle's trigger can exile it to be recast. Meanwhile, Grimgrin, Corpse-Born acts as the mandatory sacrifice outlet that continuously untaps itself and grows with infinite +1/+1 counters, while Rakdos uses the sacrificed creature's mana value to peel away and let you play your entire library.