That worked! I shut down steam and killed him once more and kosic appeared after that. Thanks!
I've successfully got myself to the thorne room and conforted Raedric and killed him. But after that nothing happens and journal entry is still the same as before confrontation. Tried twice (hell of a fight!) and the same result. What am I missing? Dxdiag, Save game files before and after confrontation and output log on the attached link on 7zip file. Btw your file attach system doesn't allow bigger than 507KB files, one save game zip is over 800KB. Thank you.