I didn't try to fight Dra'argus the Mighty, but I could get a friendly faction with his clan, I can walk between the flamethrowers & stand with Dra'argus, I could get many screen shots for him in many positions.
I killed the soldiers for many hours (Was soloing them) & I got the friendly faction with Dra'argus & his whole clan, none of them tries to kill me or fight
I couldn't understand for what the sphere is, it's just roaming in a room above Dra'argus, it cons purple & it was neutral to me.
BTW, I didn't think to attack him & I was the only one who got the friendly faction.