Activate Helm of Obedience by paying {1} and tapping it, causing target opponent to mill a card.
Due to Dauthi Voidwalker's replacement effect, the milled card is exiled instead of going to the graveyard, and that opponents repeats that process until their library is empty.

Exile target opponent's library

Helm of Obedience

Dauthi Voidwalker

Activate Lightning Greaves' equip ability by paying {0}, attaching it to any Dauthi Voidwalker you control except the one with Infinite Reflection attached.
Activate the Dauthi Voidwalker with Lightning Greaves attached by tapping and sacrificing it.
If the creature was owned by an opponent, it is exiled with a void counter instead of being put into its owner's graveyard.
Resolve the Dauthi Voidwalker ability, causing you to cast a creature card from an opponent's exile without paying its mana cost.
The creature enters the battlefield as a copy of Dauthi Voidwalker due to Infinite Reflection.
Repeat.

Infinite death triggers

Infinite creature ETB

Infinite creature LTB

Infinite creature sacrifice triggers

Infinite storm count

Infinite Reflection

Lightning Greaves

Activate a Dauthi Voidwalker that does not have Infinite Reflection attached by tapping and sacrificing it.
If the creature was owned by an opponent, it is exiled with a void counter instead of being put into its owner's graveyard.
Resolve the Dauthi Voidwalker ability, causing you to cast a creature card from an opponent's exile without paying its mana cost.
The creature enters the battlefield as a copy of Dauthi Voidwalker due to Infinite Reflection.
Repeat.

Akroma's Memorial

During the end step prior to your turn, activate Grinning Totem by paying {2} and tapping it, causing you to search an opponent's library for an instant or sorcery card that can target a creature and exile it with the ability to cast it until your next upkeep.
At the beginning of your upkeep, Grinning Totem triggers, attempting to put the instant or sorcery into its owners graveyard, but instead exiling it with a void counter due to Dauthi Voidwalker.
Activate Dauthi Voidwalker by tapping and sacrificing it, causing you to cast the instant or sorcery without paying its mana cost, targeting Tethmos High Priest.
Tethmos High Priest triggers, returning Dauthi Voidwalker from your graveyard to the battlefield.
Holding priority, activate Lightning Greaves' equip ability by paying {0}, attaching it to Tethmos High Priest.
Resolve the instant or sorcery spell, causing it to do nothing as Tethmos High Priest is now an illegal target, and then exile it with a void counter on it due to Dauthi Voidwalker.
Activate Lightning Greaves' equip ability by paying {0}, attaching it to Dauthi Voidwalker.
Repeat from step 3.

Combos with "Dauthi Voidwalker"