Derevi, Empyrial Tactician, Aether Vial, Cloudstone Curio, and Deceiver Exarch

Prerequisites

• Derevi, Empyrial Tactician on the battlefield
• Aether Vial on the battlefield
• Cloudstone Curio on the battlefield
• Deceiver Exarch in hand
• Aether Vial has exactly three charge counters on it

Steps

1. Activate Aether Vial by tapping it, putting Deceiver Exarch onto the battlefield from your hand
2. When Deceiver Exarch enters the battlefield, it and Cloudstone Curio trigger
3. Resolve the Deceiver Exarch trigger, untapping Aether Vial
4. Resolve the Cloudstone Curio trigger, returning Derevi from the battlefield to your hand
5. Activate Aether Vial by tapping it, putting Derevi onto the battlefield from your hand
6. When Derevi enters the battlefield, it and Cloudstone Curio trigger
7. Resolve the Derevi trigger, untapping Aether Vial
8. Resolve the Cloudstone Curio trigger, returning Deceiver Exarch from the battlefield to your hand
9. Repeat

Results

• Infinite ETB
• Infinite LTB