Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight + Grimgrin, Corpse-Born + Cayth, Famed Mechanist

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

Grimgrin, Corpse-Born

Cayth, Famed Mechanist

How it works

1. Activate Grimgrin by sacrificing Cayth.
2. When Cayth dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. When Cayth enters, its fabricate ability triggers, putting a +1/+1 counter on it.
4. Resolve the Grimgrin ability.
5. Repeat.