Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight + Ambitious Aetherborn + Yahenni, Undying Partisan

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

Ambitious Aetherborn

Yahenni, Undying Partisan

How it works

1. Activate Yahenni 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 Yahenni ability.
5. Repeat.