Activate Ashnod's Altar by sacrificing Guan Yu, adding {C}{C}.
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.
Repeat.

Infinite colorless mana

Infinite death triggers

Infinite creature ETB

Infinite creature LTB

Infinite creature sacrifice triggers

Guan Yu, Sainted Warrior

Remembrance

Deathrender

Ashnod's Altar

Activate Ashnod's Altar by sacrificing Guan Yu, adding {C}{C}.
Guan Yu and Verdant Succession trigger.
Resolve the Guan Yu trigger, shuffling it into your library.
Resolve the Verdant Succession trigger, searching your library for Guan Yu, putting it onto the battlefield and shuffling your library.
Repeat.

Verdant Succession

Painter's Servant

Activate Phyrexian Altar by sacrificing Guan Yu, adding one mana of any color.
Guan Yu and Verdant Succession trigger.
Resolve the Guan Yu trigger, shuffling it into your library.
Resolve the Verdant Succession trigger, searching your library for Guan Yu, putting it onto the battlefield and shuffling your library.
Repeat.

Infinite colored mana

Phyrexian Altar

Activate Altar of Dementia by sacrificing Guan Yu.
Guan Yu and Verdant Succession trigger.
Resolve the Guan Yu trigger, shuffling it into your library.
Resolve the Verdant Succession trigger, searching your library for Guan Yu, putting it onto the battlefield and shuffling your library.
Resolve the Altar of Dementia ability from step 1, causing target player to mill cards equal to Guan Yu's power.
Repeat.

Infinite mill

Infinite self-mill

Altar of Dementia

Combos with "Guan Yu, Sainted Warrior"