Ravon uses a whip, Cabdru had an axe. Sure, Ravon could switch to whip but it'd be risky and tricky with unholy grip. His whip could be stolen, or Cabdru could just bash him into the ground without his unholy up.
Ravon could transfer his unholy into an axe, but that'd just be a nuisance for him, plus, isn't cleave str and sized based?
There's also the probability that Cabdru knows some insta kill uber rare leet item that he never brought out as Cabdru, or some trick that would trap and kill Ravon.
Cabdru > Ravon.