I had no problems whatsoever with my level 34 ranger / warrior equipped with the Hunter bow. When the fight started I dodged behind the colums and fired exploding arrow a couple of times. That left me with the two main bosses. My pet and a summoned Ghost distracted Zandalor and I had my hands free to dance around and shoot exploding arrows now and then. Took ˝ a minute or so.

(Exploding arrows are way overpowered. Killed Kali in 2 shots)

"Look at you, hacker. A pathetic creature of meat and bone. Panting and sweating as you run through my corridors. How can you challenge a perfect immortal machine?"