Each opponent has a life total that is less than or equal to their library size
({1} magic symbol) ({U} magic symbol) ({B} magic symbol) available plus an additional ({2} magic symbol) ({U} magic symbol) ({B} magic symbol) for each opponent you have
Steps
Activate
Duskmantle Guildmage's first ability by paying ({1} magic symbol) ({U} magic symbol) ({B} magic symbol) , causing your opponent to lose life whenever a card is put into their graveyard this turn
Activate
Duskmantle Guildmage's second ability by paying ({2} magic symbol) ({U} magic symbol) ({B} magic symbol) , causing an opponent to mill two cards
Duskmantle Guildmage triggers twice
Resolve the first trigger, causing the opponent to lose 1 life
Mindcrank triggers, causing the opponent to mill a card
Duskmantle Guildmage triggers, causing the opponent to lose 1 life
Repeat from step 5 until the opponent has a life total of zero, causing them to lose the game