Vertebrae's intense desire to craft and build her skeleton creatures is obviously influenced by Vermin's programming. BUT Vermin wasn't the only one with an intense desire for a familial bond, Mr. Trickster though he doesn't really show it, also is very family oriented.
Mr. Trickster had of course Giggle his SO and favorite person in the world but he also has his circus troupe. A rag-tag team of lesser demons he took under his wing over the years and who over time grew to be his family.
So both minds combined had that demand for family and closeness but Vertebrae being a new thing entirely doesn't have anyone to call her family. And her hunger prevents her from viewing most living creatures as more than just food so she latched on to the next best thing which was those creatures remains.
The magical knowledge of Mr. Trickster still lingers in her mind so she knew raising the remains was possible and Vermin's ability to spawn hybrid creatures was the blueprints for her wanting to mash skeletons together to make something brand new.
When Vertebrae first emerged all she felt was hunger and loneliness so after attempting to make a meal of a deer and realizing she didn't enjoy the taste, (she /can/ eat most fauna but she cannot survive on it alone she needs to eat humans to live) she instead found another use for the carcass and so that's where it all started.
I'm not entirely sure how Vertebrae would react to genuine attempts of others trying to get close to her. Mainly because she currently doesn't see living creatures as anything other than potential food or tools.
She has yet to look someone in the eye and realize 'oh this…is a living creature who I don't want to wait til their dead to care about'
Would she be willing to allow herself to grow close to someone without the desire to just rip their flesh off to skip a few steps in keeping them in her family forever? ┐༼ ͡° ͜ʖ ͡°༽┌
