Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight + Ashnod's Altar + Pyreheart Wolf

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

Ashnod's Altar

Pyreheart Wolf

How it works

1. Activate Ashnod's Altar by sacrificing Pyreheart Wolf
2. When Pyreheart Wolf dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
3. Activate Ashnod's Altar by sacrificing Pyreheart Wolf
4. When Pyreheart Wolf dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
5. Pyreheart Wolf enters and dies as a state-based action due to having 0 toughness. Its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
6. Repeat from step 3.

This clever loop centers around Isilu, Carrier of Twilight—the reverse face of Eirdu, Carrier of Dawn—which grants persist to your other nontoken creatures. When you sacrifice Pyreheart Wolf to Ashnod's Altar, its undying ability brings it back with a +1/+1 counter, and sacrificing it again triggers Isilu's newly-bestowed persist to return it with a -1/-1 counter. Thanks to Magic's state-based actions, those opposing counters immediately annihilate each other upon the Wolf's return, resetting its counterless state so you can feed it back into the Altar indefinitely.