Nim Deathmantle, Ashnod's Altar, Xorn, and Skullport Merchant

Prerequisites

• Nim Deathmantle on the battlefield
• Ashnod's Altar on the battlefield
• Xorn on the battlefield
• Skullport Merchant on the battlefield
• available

Steps

1. Activate Ashnod's Altar by sacrificing Skullport Merchant, adding
2. Skullport Merchant dies, triggering Nim Deathmantle, causing you to pay to return Skullport Merchant from your graveyard to the battlefield, and attach Nim Deathmantle to it
3. Skullport Merchant enters the battlefield, creating two Treasure tokens
4. Activate two Treasure tokens by tapping and sacrificing those, adding two mana of any color
5. Repeat

Results

• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers