Mortuary + Daxos, Blessed by the Sun + Bolas's Citadel + Blood Pet

Mortuary

Daxos, Blessed by the Sun

Bolas's Citadel

Blood Pet

How it works

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

This clever loop turns the cycle of life and death into a self-sustaining engine using Bolas's Citadel to cast spells directly from the top of your library for a life payment instead of mana. When you sacrifice Blood Pet for black mana, Mortuary catches it on its way to the graveyard and immediately places it right back on top of your library, bypassing the mana cost entirely while the Citadel lets you recast it for just 1 life. Meanwhile, Daxos, Blessed by the Sun acts as your emotional anchor and life source, steadily padding your total by granting you 1 life every single time Blood Pet enters the battlefield and dies, effortlessly offsetting the life you pay to the Citadel.