Activate Phyrexian Altar twice by sacrificing Eternal Witness, adding {B}.
Repeat step 1 for each other nontoken creature you control.
Cast Rise of the Dark Realms by paying {7}{B}{B}, returning all creature cards from all graveyards to the battlefield under your control.
When Eternal Witness enters the battlefield, it triggers, returning Rise of the Dark Realms to your hand from your graveyard.
Repeat.

Infinite creature LTB

Infinite creature ETB

Infinite colored mana

Infinite creature sacrifice triggers

Infinite death triggers

Infinite storm count

Infinite magecraft triggers

Return all creature cards from all graveyards to the battlefield under your control

Rise of the Dark Realms

Phyrexian Altar

Eternal Witness

Activate Blood Pet by sacrificing it, adding {B}.
When Blood Pet dies, its undying ability triggers, returning it to the battlefield from your graveyard with a +1/+1 counter on it.
Activate Blood Pet by sacrificing it, adding {B}.
Activate Ashnod's Altar twice by sacrificing Eternal Witness and another nontoken non-Human creature, adding {C}{C}{C}{C}.
When the non-Human creature dies, its undying ability triggers, returning it to the battlefield from your graveyard with a +1/+1 counter on it.
Activate Ashnod's Altar twice by sacrificing Mikaeus and the non-Human creature, adding {C}{C}{C}{C}.
Cast Rise of the Dark Realms by paying {7}{B}{B}, putting all creature cards from all graveyards onto the battlefield under your control.
When Eternal Witness enters the battlefield, it triggers, returning Living Death to your hand from your graveyard.
Repeat.

Infinite colorless mana

Mikaeus, the Unhallowed

Ashnod's Altar

Blood Pet

Activate Blood Pet by sacrificing it, adding {B}.
When Blood Pet dies, its undying ability triggers, returning it to the battlefield from your graveyard with a +1/+1 counter on it.
Activate Blood Pet by sacrificing it, adding {B}.
Activate Ashnod's Altar twice by sacrificing Timeless Witness and another nontoken non-Human creature, adding {C}{C}{C}{C}.
When the non-Human creature dies, its undying ability triggers, returning it to the battlefield from your graveyard with a +1/+1 counter on it.
Activate Ashnod's Altar twice by sacrificing Mikaeus and the non-Human creature, adding {C}{C}{C}{C}.
Cast Rise of the Dark Realms by paying {7}{B}{B}, putting all creature cards from all graveyards onto the battlefield under your control.
When Timeless Witness enters the battlefield, it triggers, returning Living Death to your hand from your graveyard.
Repeat.

Timeless Witness

Activate Blood Pet by sacrificing it, adding {B}.
When Blood Pet dies, its undying ability triggers, returning it to the battlefield from your graveyard with a +1/+1 counter on it.
Activate Blood Pet by sacrificing it, adding {B}.
Activate Ashnod's Altar twice by sacrificing Ardent Elementalist and another nontoken non-Human creature, adding {C}{C}{C}{C}.
When the non-Human creature dies, its undying ability triggers, returning it to the battlefield from your graveyard with a +1/+1 counter on it.
Activate Ashnod's Altar twice by sacrificing Mikaeus and the non-Human creature, adding {C}{C}{C}{C}.
Cast Rise of the Dark Realms by paying {7}{B}{B}, putting all creature cards from all graveyards onto the battlefield under your control.
When Ardent Elementalist enters the battlefield, it triggers, returning Living Death to your hand from your graveyard.
Repeat.

Ardent Elementalist

Activate Blood Pet by sacrificing it, adding {B}.
When Blood Pet dies, its undying ability triggers, returning it to the battlefield from your graveyard with a +1/+1 counter on it.
Activate Blood Pet by sacrificing it, adding {B}.
Activate Ashnod's Altar twice by sacrificing Archaeomancer and another nontoken non-Human creature, adding {C}{C}{C}{C}.
When the non-Human creature dies, its undying ability triggers, returning it to the battlefield from your graveyard with a +1/+1 counter on it.
Activate Ashnod's Altar twice by sacrificing Mikaeus and the non-Human creature, adding {C}{C}{C}{C}.
Cast Rise of the Dark Realms by paying {7}{B}{B}, putting all creature cards from all graveyards onto the battlefield under your control.
When Archaeomancer enters the battlefield, it triggers, returning Living Death to your hand from your graveyard.
Repeat.

Combos with "Rise of the Dark Realms"