The Rentar fight was appropriately difficult I believe. Perhaps somewhat static in that nothing really happens beyond her trying to cast various powerful spells which the crystal you have blocks. Though, it should not be forgotten that if one smashes the crystal then the fight will be much more difficult. I smashed the crystal shard the first time through and found myself having a tense fight. Dorkas was definitely the most interesting fight throughout the game. The setting . . . well he was in Avernum not the Empire so he really couldn't build that much beyond what Erika's basement consisted off.