The orges were hostile to the tieflings from their perspective, the orges are classified as your summons from the horn item, shortly after summoning, you can see when one of the orges had that awkward turn doing basically nothing trying to possibly target a closer tiefling, after the end of Zevlor's turn he and the tieflings are registered you as hostile, basically lumping you with the ogres. The orges did say they kill all around them.
Most likely your Ogres made everyone hostile because they attack everyone but the summoner. If you knock out someone who is not temporarily hostile they will be considered dead. Cerys is indeed a back up Zevlor in case he dies in the fight. She was out scouting and you normally meet her in the inn in Act 2. Great fight, though throwing out the Spectator was questionable tactics.
The orges were hostile to the tieflings from their perspective, the orges are classified as your summons from the horn item, shortly after summoning, you can see when one of the orges had that awkward turn doing basically nothing trying to possibly target a closer tiefling, after the end of Zevlor's turn he and the tieflings are registered you as hostile, basically lumping you with the ogres. The orges did say they kill all around them.
Most likely your Ogres made everyone hostile because they attack everyone but the summoner. If you knock out someone who is not temporarily hostile they will be considered dead. Cerys is indeed a back up Zevlor in case he dies in the fight. She was out scouting and you normally meet her in the inn in Act 2. Great fight, though throwing out the Spectator was questionable tactics.
Maybe throwing out the Specter turned everyone hostile? I didn't see anything other than that.