The first time I got into this fight, I also thought this was the end-of-game. Never would I be able to finish act 2. But, as usual, after a few retries you find a strategy that can work.
Althought there's still an important dependance on the die rolls, IMO. Especially those from Dame Aylin. Sometimes she's as harmful (not) as a fly and gets swatted just as easily. Other times she wacks Ketheric like a training dummy.