I might keep her, might not, I want to draw her w the celestia/chrysalis i did lmao, maybe the celestia/discord im working on
 
working idea:  
im thinking she n her father live in a small arctic-type town and shes like a watchman, she keeps lanterns lit at night and appears to guide lost ponies in a way similar to how her mother appears in dreams to help  
sombra probably looks way less evil, and while her luna has to stay in canterlot and generally keep her family a secret (theyll probably be revealed to the public eventually), she visits them often  
this is probably after sombras return and etc and he probably lost his horn/maybe memories? but he has nightmares constantly about what he had done n that was how luna discovered that he was still alive  
they bonded over villain history and corruption n etc and became very close  
celestia totally knows and loves her niece to bits
 
theres a year or so age difference between celestias kid and lunas, lunas being the older one bc celestia is super busy n she doesnt have a ton of time for Romance yk