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

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

Morselhoarder

Yahenni, Undying Partisan

How it works

1. If Morselhoarder has any -1/-1 counters on it, activate it by removing a -1/-1 counter from it, adding one mana of any color.
2. Repeat step 1 as necessary until Morselhoarder has no -1/-1 counters on it.
3. Activate Yahenni by sacrificing Morselhoarder.
4. When Morselhoarder dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
5. Resolve the Yahenni ability.
6. Repeat.

This clever loop transforms a simple mechanical quirk into a self-sustaining engine, turning Morselhoarder into an infinite mana and death trigger machine. Thanks to the back side of Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight granting persist to your other nontoken creatures, Morselhoarder returns from the grave with a -1/-1 counter whenever it dies. You can then use Morselhoarder's own ability to strip away those very -1/-1 counters for colored mana before feeding it to Yahenni, Undying Partisan's sacrifice outlet. Yahenni happily grows larger with each iteration while keeping the loop safe, allowing you to generate unbounded mana and triggers at will.