Is it just for me or is Fighting Lord Harkon the glitchiest [censored] EVER! First of all he can regain all his health in about two seconds and when im just about to kill him he just stands there and slowly regains health and cannot take damage. He also sometimes stays in his bat form and dosn't die, aswel as staying in that big red orb thing and not coming out!

Have you tyed the bow yet? It's a common mistake

Use Au-riel's bow against him. Hit the red sphere and it will vanish in light.