Activate Ashnod's Altar by sacrificing Grave Titan, adding {C}{C}.
When Grave Titan dies, Nim Deathmantle triggers, causing you to pay {4} to return Grave Titan from your graveyard to the battlefield and attach Nim Deathmantle to it.
When Grave Titan enters, it triggers, creating two creature tokens.
Activate Ashnod's Altar by sacrificing a creature token, adding {C}{C}.
Repeat.

Infinite colorless mana

Infinite creature tokens

Infinite death triggers

Infinite ETB

Infinite LTB

Infinite sacrifice triggers

Nim Deathmantle

Ashnod's Altar

Grave Titan

Declare Grave Titan and the creature with Breath of Fury attached as attackers.
Grave Titan triggers, creating two 2/2 Zombie creature tokens.
Deal combat damage using the creature that has Breath of Fury attached.
Breath of Fury triggers, causing you to sacrifice the creature it is attached to, then attach Breath of Fury to a Zombie token, then causing you to untap all creatures you control and to get an additional combat phase after this one.
Repeat each combat phase.


Infinite combat damage

Infinite combat phases

Infinite mana creatures you control can produce

Infinite untap of creatures you control

Infinite creature tokens with haste

Breath of Fury

Anger

Fervor

Urabrask the Hidden

Mass Hysteria

Roar of Resistance

Combos with "Grave Titan"