SWTOR: Echoes of Oblivion

Here's the fight at the end of the mission with Valkorion, Vitiate, and Tenebrae. I did some "testing" of the objects around me so you can see damage. Essentially, you will be nearly invincible and healed by the group assisting you. I'm not sure of the exact mechanics, but here pay attention to damage and what the team is doing. When they break off on adds, go after them as well. Also, use the team buttons to coordinate strikes.