Guan Yu, Sainted Warrior + Remembrance + Deathrender + Phantom Train

Guan Yu, Sainted Warrior

Remembrance

Deathrender

Phantom Train

How it works

1. Activate Phantom Train by sacrificing Guan Yu.
2. When Guan Yu dies, it, Deathrender and Remembrance trigger.
3. Resolve the Guan Yu trigger, causing you to shuffle it into your library from your graveyard.
4. Resolve the Remembrance trigger, causing you to search your library for Guan Yu and put it into your hand.
5. Resolve the Deathrender trigger, putting Guan Yu from your hand onto the battlefield, and attaching Deathrender to it.
6. Resolve the Phantom Train ability
7. Repeat.

This ingenious loop turns Guan Yu, Sainted Warrior into a self-sustaining engine by exploiting his own replacement-like death trigger alongside Remembrance. When you sacrifice Guan Yu to fuel Phantom Train's ability, his own graveyard trigger attempts to shuffle him into your library, but Remembrance allows you to bypass that by tutoring him straight to your hand instead. From there, Deathrender's triggered ability steps in, instantly dropping Guan Yu back onto the battlefield and equipping itself to him so the cycle can begin anew.