Sin, Unending Cataclysm + Aura of Dominion + Altar of Dementia + Arbor Adherent

Sin, Unending Cataclysm

Aura of Dominion

Altar of Dementia

Arbor Adherent

How it works

1. Cast Sin either from your hand or command zone by paying 5 plus commander tax if applicable.
2. As Sin enters, remove all counters from all artifacts, enchantments and creatures you control, putting twice that many +1/+1 counters on Sin.
3. Activate Arbor Adherent by tapping it, adding an amount of or equal to Sin's toughness.
4. Activate Aura of Dominion by paying 1 and tapping Sin, untapping Arbor Adherent.
5. Activate Altar of Dementia by sacrificing Sin.
6. Choose to return Sin to the command zone from your graveyard.
7. When Sin dies, it triggers, putting its counters on Arbor Adherent.
8. Resolve the Altar of Dementia ability.
9. Repeat.

This loop transforms a massive stack of counters into an absolute engine of destruction by leveraging the scaling power of Sin, Unending Cataclysm. When Sin enters the battlefield, it feasts on your existing counters to grow massive, which in turn supercharges Arbor Adherent's mana production due to Sin's towering toughness. You can then tap Sin to pay for Aura of Dominion's activation, untapping Arbor Adherent to fuel the loop while using Altar of Dementia to sacrifice Sin and mill your opponents out of the game. Because Sin shuffles itself back or returns to the command zone and retains its ability to re-enter and absorb counters anew, every iteration continuously recycles its enormous stat growth into infinite mana, sacrifices, and mill.