Based on Glasya's battle dialogue, he seems to be loyal to the Empire and Amon; he seems to be proud of his power given to him by Amon.
Scylla on the other hand seems more like her transformation was forced on her and was relieved to finally die. I just want to know just what nation Scylla was Queen of? I figured that she may have been the reigning monarch of the Empire prior to Xande's resurrection by Amon and was transformed as punishment for allowing the Empire to be so weak.But if that was the case shouldn't she be called "Empress" instead?
Her being a captured Queen of Sophia's nation is a possibility. That is what they did with Tiamat, more or less.