Remembrance + Deathrender + Arashin Sovereign + Umbral Collar Zealot

Remembrance

Deathrender

Arashin Sovereign

Umbral Collar Zealot

How it works

1. Activate Umbral Collar Zealot by sacrificing Arashin Sovereign.
2. When Arashin Sovereign dies, it, Deathrender and Remembrance trigger.
3. Resolve the Arashin Sovereign trigger, causing you to put it on top of your library from your graveyard.
4. Resolve the Remembrance trigger, causing you to search your library for Arashin Sovereign and put it into your hand.
5. Resolve the Deathrender trigger, putting Arashin Sovereign from your hand onto the battlefield, and attaching Deathrender to it.
6. Resolve the Umbral Collar Zealot ability
7. Repeat.

This looping engine starts when you use Umbral Collar Zealot to sacrifice Arashin Sovereign, sending the mighty dragon to the graveyard and triggering a cascade of simultaneous events. Deathrender uses this death to instantly cheat Arashin Sovereign right back onto the battlefield from your hand, re-equipping itself to the dragon for the next cycle. Meanwhile, Remembrance takes advantage of the same death to fetch a copy of Arashin Sovereign straight out of your library and into your hand, ensuring you never run out of ammo. The dragon's own built-in dying trigger lets you return it to the top of your library if needed, and Umbral Collar Zealot's sacrifice ability is fueled indefinitely to keep the chain of deaths, enters-the-battlefield effects, and surveil triggers going forever.