When the fight ends, Erandur laments, “I… knew Veren and Thorek. They were my friends. Is this punishment for my past? Is it Mara’s will to torment me so?”
J’Zhirr reminds Erandur that we had no choice as they attacked us. Erandur agrees with this one’s logic and performs the ritual to destroy the Skull. While Erandur is casting the spell, J’Zhirr hears a woman’s voice. There is no reaction from Erandur so J’Zhirr seems to be the only one who hears her.
She says, “He’s deceiving you. When the ritual’s complete, the Skull will be free and then Erandur will turn on you. Quickly! Kill him now. Kill him and claim the Skull for your own! Vaermina commands you!”
But J’Zhirr does nothing. This one is wary of listening to Daedric Princes, especially after meeting Clavicus Vile.