Mortuary + Yahenni, Undying Partisan + Tarpan + Gwenom, Remorseless

Mortuary

Yahenni, Undying Partisan

Tarpan

Gwenom, Remorseless

How it works

1. Activate Yahenni by sacrificing Tarpan.
2. When Tarpan dies, it and Mortuary triggers.
3. Resolve the Mortuary trigger, putting Tarpan from your graveyard onto the top of your library.
4. Resolve the Tarpan trigger, causing you to gain 1 life
5. Resolve the Yahenni ability.
6. Cast Tarpan from the top of your library by paying 1 life due to Gwenom.
7. Repeat.

This loop relies on a clever death-and-return cycle that turns a tiny green beast into an endless engine, fueled entirely by the life you have to spare. By using Yahenni, Undying Partisan to repeatedly sacrifice Tarpan, you trigger Mortuary to immediately recycle Tarpan right back to the top of your library instead of letting it rest in the graveyard. Once Tarpan is sitting comfortably on top of your library, Gwenom, Remorseless lets you cast it straight from there for a meager payment of 1 life instead of its mana cost—an offset easily sustained by the 1 life you gain each time Tarpan dies.