Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight + Ambitious Aetherborn + Grimgrin, Corpse-Born

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

Ambitious Aetherborn

Grimgrin, Corpse-Born

How it works

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