Mortuary + Crimson Kobolds + Bolas's Citadel + Phantom Train

Mortuary

Crimson Kobolds

Bolas's Citadel

Phantom Train

How it works

1. Activate Phantom Train by sacrificing Crimson Kobolds
2. When Crimson Kobolds dies, Mortuary triggers, putting Crimson Kobolds from your graveyard onto the top of your library.
3. Resolve the Phantom Train ability.
4. Cast Crimson Kobolds from the top of your library by paying 0 life.
5. Repeat.

This loop turns the zero-mana cost of Crimson Kobolds into an engine for infinite triggers by leveraging Mortuary, which instantly recycles the Kobold to the top of your library every time it dies. Bolas's Citadel makes that top-deck placement matter by letting you recast the creature straight from the library for zero life, bypassing traditional mana costs entirely. Meanwhile, Phantom Train serves as the necessary sacrifice outlet to trigger the graveyard loop while accumulating a mountain of +1/+1 counters on itself along the way.