Remembrance + Deathrender + Arashin Sovereign + Altar of Dementia

Remembrance

Deathrender

Arashin Sovereign

Altar of Dementia

How it works

1. Activate Altar of Dementia 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 Altar of Dementia ability, causing target player to mill cards equal to Arashin Sovereign's power.
7. Repeat.

This clever loop uses Altar of Dementia as the sacrifice outlet to send Arashin Sovereign straight to the graveyard, where its death trigger lets you place it back on top of your library. From there, Remembrance swoops in to tutor that exact same Arashin Sovereign from your library directly into your hand, bypassing traditional draw steps entirely. As all of this happens, Deathrender catches the creature as it dies, instantly sliding onto the newly cast Arashin Sovereign from your hand to ensure the whole cycle can repeat indefinitely while milling your opponent's entire library into oblivion.