Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight + Mikaeus, the Unhallowed + Grimgrin, Corpse-Born

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

Mikaeus, the Unhallowed

Grimgrin, Corpse-Born

How it works

1. Activate Grimgrin by sacrificing another nontoken non-Human creature
2. When the creature dies, its undying ability triggers, returning the creature from your graveyard to the battlefield with a +1/+1 counter on it.
3. Activate Grimgrin by sacrificing the creature with a +1/+1 counter on it.
4. When the creature dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
5. Resolve the Grimgrin abilities from step 1 and 3.
6. Repeat.