Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight + Flayer of the Hatebound + Phyrexian Altar

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

Flayer of the Hatebound

Phyrexian Altar

How it works

1. Activate Phyrexian Altar by sacrificing Flayer of the Hatebound
2. When Flayer of the Hatebound dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
3. When Flayer of the Hatebound enters, it triggers, dealing damage equal to its power to any target.
4. Activate Phyrexian Altar by sacrificing Flayer of the Hatebound
5. When Flayer of the Hatebound dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
6. When Flayer of the Hatebound enters, it triggers, dealing damage equal to its power to any target.
7. Repeat.

This loop turns Flayer of the Hatebound into an endless loop of damage and sacrifice by bouncing it back and forth between the graveyard and the battlefield. Phyrexian Altar provides the easy sacrifice outlet while producing the mana needed to keep the cycle going. The missing piece of the puzzle is supplied by the back side of Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight, which grants Flayer of the Hatebound persist—allowing it to alternate between undying and persist counters so it can continuously cheat death and trigger its own entry damage over and over again.