Stalwart Successor + Yahenni, Undying Partisan + Lingering Tormentor

Stalwart Successor

Yahenni, Undying Partisan

Lingering Tormentor

How it works

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

This loop relies on Stalwart Successor to counteract the drawback of Lingering Tormentor's persist ability, turning each death and resurrection into a net-zero counter state that can be repeated indefinitely. Whenever you sacrifice Lingering Tormentor to fuel Yahenni, Undying Partisan's activation for temporary indestructible protection, the persist trigger brings it right back with a -1/-1 counter. That fresh entry immediately sparks Stalwart Successor's ability because it is the first time counters have been placed on the Tormentor that turn, slapping a +1/+1 counter on it that cancels out the -1/-1 counter entirely. Because the creature returns to the battlefield clean of counters every single time, you can continuously feed Yahenni, Undying Partisan to generate an endless stream of sacrifice, death, and entry triggers.