Mortuary + Blood Pet + Vengeful Bloodwitch + Gwenom, Remorseless

Mortuary

Blood Pet

Vengeful Bloodwitch

Gwenom, Remorseless

How it works

1. Activate Blood Pet by sacrificing it.
2. When Blood Pet dies, Mortuary and Vengeful Bloodwitch trigger.
3. Resolve the Mortuary trigger, putting Blood Pet from your graveyard onto the top of your library.
4. Resolve the Vengeful Bloodwitch trigger, causing you to gain 1 life and target opponent to lose 1 life.
5. Cast Blood Pet from the top of your library by paying 1 life.
6. Repeat.

This ingenious loop lets you sacrifice Blood Pet for mana, triggering Vengeful Bloodwitch to drain your opponent while Mortuary quietly catches the creature and places it right back onto your library. Gwenom, Remorseless then transforms the top of your library into a hidden staging ground, letting you recast that very same Blood Pet using life instead of mana to pay its cost. Because Blood Pet only costs one mana, you can easily pay the life equivalent to keep the engine spinning indefinitely, turning a simple sacrifice into an endless cycle of life drain.