Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight + Ashnod's Altar + Arcbound Tracker
Produces: Infinite LTB, Infinite ETB, Infinite sacrifice triggers, Infinite death triggers, Infinite colorless mana, Infinite +1/+1 counters on certain creatures
- Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight
- Ashnod's Altar
- Arcbound Tracker
- Color identity
- RWB
Steps
- Activate Ashnod's Altar by sacrificing Arcbound Tracker.
- When Arcbound Tracker dies, its modular ability and persist ability trigger.
- Resolve the modular trigger, putting Arcbound Tracker's +1/+1 counters on another artifact creature.
- Resolve the persist trigger, returning Arcbound Tracker from your graveyard to the battlefield. It will not have a -1/-1 counter on it due to its modular ability.
- Repeat.