When Guan Yu dies, it, Deathrender and Remembrance trigger.
Resolve the Guan Yu trigger, causing you to shuffle it into your library from your graveyard.
Resolve the Remembrance trigger, causing you to search your library for Guan Yu and put it into your hand.
Resolve the Deathrender trigger, putting Guan Yu from your hand onto the battlefield, and attaching Deathrender to it.
Resolve the Viscera Seer ability, causing you to scry 1.
Repeat.
This clever recursive loop turns Viscera Seer into a perpetual engine by sacrificing Guan Yu, Sainted Warrior to trigger a cascade of overlapping replacement and death effects. Because Guan Yu's own triggered ability tries to shuffle it into your library when it hits the graveyard, you would normally lose track of it—but Remembrance intercepts this moment, allowing you to reliably tutor the legendary warrior straight back to your hand instead. From there, Deathrender’s triggered ability swoops in to cheat Guan Yu directly onto the battlefield while re-equipping itself for the next iteration, letting you repeat the cycle indefinitely to sculpt your draws with infinite scries.