Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight + Solemnity + Phyrexian Altar

Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight

Solemnity

Phyrexian Altar

How it works

1. Activate Phyrexian Altar by sacrificing another nontoken creature without a -1/-1 counter on it.
2. When the creature dies, its persist ability triggers, returning it from your graveyard to the battlefield without a -1/-1 counter on it due to Solemnity.
3. Repeat.

This elegant loop turns a simple sacrifice outlet into an infinite engine by neutralizing its primary drawback. With Solemnity preventing counters from ever being placed, any nontoken creature you feed to Phyrexian Altar can immediately return via its persist ability, completely ignoring the usual -1/-1 counter penalty. Meanwhile, Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight provides the crucial background enablement by granting that persist ability to your other nontoken creatures the moment it flips to its twilight side. By cycling your creatures endlessly through the graveyard, you generate an infinite stream of colored mana alongside endless sacrifice, death, and entry triggers.