Kraven gives exposition that Spiderman is his greatest challenge ever and vows to capture him 

Kraven tranquilizes Spiderman to a near-death state and buries him

Kraven impersonates Spiderman to prove he is superior even going so far as to murder criminals

Kraven targets a villain named Vermin to defeat and capture him- something that Cap and Spiderman had to do together

Spidey recuperates from a 2-week coma and emerges from the ground seeking Kraven for vengeance

Kraven makes Vermin fight Spidey intending on Vermin to beat Spidey which he does then intervenes when he is satisfied that he has truly beaten Spiderman in every way

He lets Vermin go, vows to never hunt again, and allows Spiderman to go after him 

Having no more sense of purpose, Kraven commits suicide by rifle

Spiderman confronts Vermin, defeats him, leaves him for the police and tells him that Mister Fantastic can help him