If you have problem to take down the priestess from the Book 14 chapter 15 these tips might be useful for you:
- Kill one of the summoned adds and then pull the other one away from the priestess. Like all protector types they absorb the damage the priestess is taking, and the priestess in turn heals them up. If the distance is broken or they are stunned this doesn't work.
- Also kill the 2 archers next to the priest at the start first
- Get the tank to interrupt where possible
- Just keep one of the adds alive for the entire fight, new adds won't spawn until both are killed.
- Prepare for a reasonably long fight in any case.