Mayael's Aria, Auriok Bladewarden, and Umbral Mantle

Prerequisites

• Mayael's Aria on the battlefield
• Auriok Bladewarden on the battlefield
• Umbral Mantle on the battlefield
• Umbral Mantle attached to Auriok Bladewarden
• (at most) available

Steps

1. At the beginning of your upkeep, Mayael's Aria triggers
2. Holding priority, activate Auriok Bladewarden by tapping it, giving itself +X/+X until end of turn, where X is its power
3. Activate Auriok Bladewarden by paying and untapping it, giving it +2/+2 until end of turn
4. Repeat from step 2 until Auriok Bladewarden has power nineteen or greater, omitting step 3 on the final iteration, if possible
5. Resolve the Mayael's Aria trigger from step 1, causing you to put a +1/+1 counter on each creature you control, gain 10 life and win the game

Results

• Win the game