Nim Deathmantle, Ashnod's Altar, Xu-Ifit, Osteoharmonist, and Concordant Crossroads Combo

Nim Deathmantle, Ashnod's Altar, Xu-Ifit, Osteoharmonist, and Concordant Crossroads

Here's how the cards Nim Deathmantle, Ashnod's Altar, Xu-Ifit, Osteoharmonist, and Concordant Crossroads results in Infinite LTB, Infinite ETB, Infinite sacrifice triggers, and Infinite death triggers

Nim Deathmantle

Ashnod's Altar

Xu-Ifit, Osteoharmonist

Concordant Crossroads

Prerequisites

Nim Deathmantle on the battlefield
Ashnod's Altar on the battlefield
Xu-Ifit, Osteoharmonist on the battlefield
Concordant Crossroads on the battlefield

Steps

Activate Ashnod's Altar by sacrificing another nontoken creature, adding
When the creature dies, Nim Deathmantle triggers
Choose not to pay
Activate Xu-Ifit by tapping it, returning a creature from your graveyard to the battlefield
Activate Ashnod's Altar by sacrificing Xu-Ifit, adding
When Xu-Ifit dies, Nim Deathmantle triggers, causing you to pay to return it from your graveyard to the battlefield and attach Nim Deathmantle to it
Repeat