Duskmantle Guildmage, and Maddening Cacophony

Prerequisites

• Duskmantle Guildmage on the battlefield
• Maddening Cacophony in hand
• Each opponent has a life total that is less than or equal to half their library size, rounded up
• available

Steps

1. Activate Duskmantle Guildmage's first ability by paying
2. Cast Maddening Cacophony with kicker by paying , causing each opponent to mill half their library, rounded up
3. Duskmantle Guildmage triggers for each card milled this way
4. Resolve the first Duskmantle Guildmage trigger, causing the opponent to lose 1 life
5. Repeat step 4 until the opponent loses the game due to having zero or less life
6. Repeat from step 4 for each remaining trigger

Results

• Each opponent loses the game
• Near-infinite lifeloss
• Near-infinite mill