Activate Kenrith's fifth ability by paying ({4} magic symbol) ({B} magic symbol) , returning Deep Forest Hermit to the battlefield from your graveyard.
When Deep Forest Hermit enters the battlefield, it triggers, creating four 1/1 Squirrel creature tokens.
Activate Phyrexian Altar five times by sacrificing Deep Forest Hermit and the four Squirrel tokens, adding ({4} magic symbol) ({B} magic symbol) .