RPG.net's friendly neighborhood Nuwisha.
Maybe, he could have been set up to fail so he must rely on Aarevos more. It's also possible he thought Viren could win, because he was doing pretty well up until he got distracted by the bird, which Aarevos might not have foreseen. I haven't made up my mind which yet.
Without Aarevos Viren would not be able to take down as many guards.
Dark Magic after all needs components and seems require more time in casting spells then primal magic, both are important in a fight.