Jeff is the real sacrifice, and Derek is the actual leader of the coven with Miranda as his co-conspirator to trap Jeff and make him voluntarily come to the sacrifice. Derek and Miranda mock Jeff and Derek kills Jeff who realizes the full extent of the plot and his betrayal, but is too late.
Jeff is the true victim, and Derek is the genuine leader of the coven with Miranda as his accomplice to lure Jeff into the sacrifice. Derek and Miranda ridicule Jeff, and Derek murders Jeff, who comes to understand the full scope of the plot and his own deception, but it's too late.