Activate Zevlor by paying ({2} magic symbol) and tapping it, causing you to copy the next spell you cast this turn that targets a single opponent for each other opponent.
Cast Peer into the Abyss by paying ({4} magic symbol) ({B} magic symbol) ({B} magic symbol) ({B} magic symbol) , targeting any opponent.
Zevlor triggers, copying Peer into the Abyss for each opponent.
Resolve each Peer into the Abyss, causing each opponent to draw cards equal to half their library size and lose half their life total, rounded up.
At the beginning of your end step, Archfiend of Despair triggers, causing each opponent to lose life equal to the life they lost this turn.
Each opponent loses the game due to having zero or less life.