Nim Deathmantle, Krark-Clan Ironworks, and Iron League Steed

Prerequisites

• Nim Deathmantle on the battlefield
• Krark-Clan Ironworks on the battlefield
• Iron League Steed on the battlefield
• available

Steps

1. Activate Krark-Clan Ironworks by sacrificing Iron League Steed, adding
2. When Iron League Steed dies, Nim Deathmantle triggers, causing you to pay to return Iron League Steed from your graveyard to the battlefield, and attach Nim Deathmantle to it
3. When Iron League Steed enters the battlefield, its fabricate ability triggers, creating a 1/1 Servo artifact creature token
4. Activate Krark-Clan Ironworks by sacrificing the Servo, adding
5. Repeat

Results

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