Nim Deathmantle, Ashnod's Altar, and Callous Bloodmage

Prerequisites

• Nim Deathmantle on the battlefield
• Ashnod's Altar on the battlefield
• Callous Bloodmage on the battlefield
• available

Steps

1. Activate Ashnod's Altar by sacrificing Callous Bloodmage, adding
2. Callous Bloodmage dies, triggering Nim Deathmantle, causing you to pay to return Callous Bloodmage from your graveyard to the battlefield, and attach Nim Deathmantle to it
3. Callous Bloodmage enters the battlefield, creating a 1/1 Pest creature token
4. Activate Ashnod's Altar by sacrificing the Pest, adding
5. When the Pest dies, it triggers, causing you to gain one life
6. Repeat

Results

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