Hello Constantin,
First of all, it's nice to see how much effort you're putting into the background of your character!
Secondly, I could see some possible connections between our characters. Eliena originates from Paris and ran her studies partly at Lumilaria. Perhaps we could've met there at some time when Eliena wasn't getting homeschooled and maybe reunite again unexpectedly after years of time at the Myrddin Emrys College? Eliena was sorted in Ibidens and will be functioning as head girl next year, meaning she possibly gets assigned to guide pupils and will follow many different classes. She strives real hard, mostly because of the pressure she gets from the homefront. Eliena was raised very strictly, as her father comes from a long and strong bloodline as well. Perhaps our families could know each other because of their history? Eliena was born ancient, but she wouldn't act too differently anymore towards demi's. Let me know if this is something you can work with!