My group started out by kiting her, but that was a massive SP drain to take her HP down to spawn spiders. After that, we moved to tanking her inside the flame, and she would occasionally run off in fear.
The thrower did a form of debuff that really let us get some good damage on her, we ended up wasting too many so the melees had a bit more difficulty in taking her HP down.
She apparently has Rogue levels, so can now sneak attack and possibly crit you with the fort bypass things. Anyone tanking or kiting her would do well to have exceptional fort.
Toward the end, when all the Hezrou's started spawning, I ended up having to Blade Barrier kite everything just to try to control things a bit.