'The legends about demons painted them as black, oily, formless beings of nightmare; shadows drawing forth from the abyss, the void between worlds. Yet the things calling themselves demons now? They're nothing like the legends! The first of them we encountered was Kasyrra, their so-called new queen: a statuesque crimson woman with traits mixing bovine, dragon, and fiend. She appeared to [pc.name] alone, tearing her way into our world through the portal in Hawkstone's temple... the same one my sister was flung through moments before.
She'd almost be beautiful if it wasn't for the black pit in her heart where her soul ought to be.
Kasyrra was the first and only of her kind in Savarra for a time, but now that we've seen what she did to Alissa... how many more broken souls has she torn from people? There will only be more demons across the Marches as we progress. One more reason we have to stop them!
After seeing Queen Alissa's transformation, there's clearly no consistent way to identify a demon... Kasyrra and her broken elven queen were wholly different beasts, though both were cloven-legged and had tails and horns. It seems evident that there's quite a bit of variety in what constitutes a demon's physical form. We can't be complacent in assuming we understand what demons look like... they may even be shapeshifters, as they can clearly change other peoples' bodies!'