Yesssssss~ I knew I saw some glimpses of unhinged devotion in there! (The stalking by proxy as an example) It's so exciting to find a story that is interested in exploring the relationship between two beings who do not necessarily share the same ideas or values when it comes to romance. Nothing drives me crazier in fiction than when you have a character who is non-human, but would be entirely human otherwise if it weren't for their odd appearance.
I do wish we had a better term for this sort of character. I love yanderes, but it does feel like the concept has become overly bloated with subgenres and sometimes leads to confusion among fans. Not to mention that an all-consuming love that prioritizes the other over the self has existed in literature since...pretty much forever.
Please don't feel pressured to categorize your characters in any way that doesn't feel right to you! I and many others already adore everything we've seen of Jack so far! You have a real talent for crafting stories and characters, thank you so much for sharing it with us!