Once again, on all these, there will be spoilers. I highly recommend you finish the story before reading these musings. Also, these are just my own feelings, nothing (not even I) says that you have to agree with them.
Sophy is named after the word philosophy, and thus, her name is pronounced the same as the second part of the word. Her name was originally going to be Murmur, to complinent Selaf’s original name, Furfur. Once Selaf wasn’t going to use that name, I decided to change Sophy’s name as well. She also does keep some traits of her namesake, though not as much.
Her characterization actually changed from my original intent. At first, I wanted Sophy to be sort of fake happy yet cynical deep down. Her smile was just a false front. I felt that would be too similar to Selaf and wouldn’t be an effective foil. Now, she really desires to be a good person in a part of society where that isn’t rewarded or even looked well on.
Her appearance was supposed to be evocative of a snake, or someone mischievious. I made it back when she was supposed to be cynical, and since I like it, I kept that appearance. It’s not more of a cat-like smirk.
Her feastend powers were more based on her name, Murmur. She can murmur in a way that’s not perceivable, yet is understandable. She’s not particularly averse to using her powers, but wouldn’t do so whenever its convenient.
Sophy’s a pretty important influence on Selaf, and is the primary driving force behind Selaf opening up. In book 2, I plan to explore more of Sophy’s past.