Vishgraz dies, triggering Nim Deathmantle, causing you to pay ({4} magic symbol) to return Vishgraz from your graveyard to the battlefield, and attach Nim Deathmantle to it.
Vishgraz enters the battlefield, creating three 1/1 Phyrexian Mite creature tokens.
Activate Phyrexian Altar three times by sacrificing the Phyrexian Mites, adding ({3} magic symbol) .