The Master, Formed Anew + Yahenni, Undying Partisan

The Master, Formed Anew

Yahenni, Undying Partisan

How it works

1. Activate Yahenni by sacrificing The Master.
2. When The Master dies, if it was a copy of the undying creature, its undying ability triggers, returning it from your graveyard to the battlefield as a copy of the persist creature with a +1/+1 counter on it.
3. Otherwise, if The Master was a copy of the persist creature, its persist ability triggers, returning it from your graveyard to the battlefield as a copy of the undying creature with a -1/-1 counter on it.
4. Resolve the Yahenni ability.
5. Repeat.