Remembrance + Mortuary + Crimson Kobolds + Yahenni, Undying Partisan

Remembrance

Mortuary

Crimson Kobolds

Yahenni, Undying Partisan

How it works

1. Activate Yahenni by sacrificing Crimson Kobolds.
2. When Crimson Kobolds dies, Mortuary and Remembrance trigger.
3. Resolve the Mortuary trigger, putting Crimson Kobolds from your graveyard on top of your library.
4. Resolve the Remembrance trigger, searching your library for Crimson Kobolds and putting it into your hand.
5. Resolve the Yahenni ability.
6. Cast Crimson Kobolds by paying 0.
7. Repeat.

This loop turns free fodder into a perpetual engine by exploiting the quirks of simultaneous triggers. When you use Yahenni, Undying Partisan to sacrifice Crimson Kobolds, both Mortuary and Remembrance trigger off the death, letting you stack the triggers so that Crimson Kobolds goes to the top of your library and a copy is tutored straight to your hand. Because Crimson Kobolds costs zero mana to cast, you can immediately replay it from your hand right back to the battlefield—where it rests safely on top of your library again once the loop restarts—generating an endless storm count and infinite sacrifice triggers to pump Yahenni to insurmountable heights.