2(DITOEFTV)

An Au where Penelope is actually the Eckhart's cousin as Penelope is the daughter of the Eckhart siblings' mother's brother who came from another kingdom which was very connected to magic and was known to have families that descend from the Ancient Mages and other magical creatures.

Penelope's father family(and the Eckhart siblings' mother too), were descendants from both an ancient mage and a magical creature(golden dragon) but the blood of both got so diluted that it was rare for any member of the family to be born with it until Penelope who was the first one born with their blood in more then 1000 years.

Leila hearing this sent some demons/subordinates to try and kill her but was unsuccessful as while she killed the rest of the family(including the siblings' mother who had been visiting her brother), Penelope's mother was able to run away with Penelope.

Things follow canon until Duke Eckhart brings Penelope home and the old nanny that had came with the siblings' mother, notices how much Penelope resembles her parents and talks with the Duke who is curious enough to know if anyone from his wife's family survives to decide and do a DNA test between Penelope, him and his two sons.

A week later, Duke Eckhart calls Penelope to his office and instead of being berated as she thought(it was could be during the collar incident or something else), the Duke informs her that he could not adopt her but could take her in as a ward since she was the heir to the ???(the writer can choose the name as nothing comes to my mind xD) family which was the one his wife came from.

Penelope doesn't have time to digest anything before she is whisked away by the old nanny and taken to get new things including books so she could learn more about the world and her family.

Reinhart and Dereck hadn't heard from Penelope for so long that they assumed their father had taken her back to the streets until the Duke called them to his office and informed them that there was a surviving member from their mother's family and the emperor had heard about it so they would be taking that person to meet the royal family just before Penelope knocked at the door and entered.

How things would go from here is up to the writer but I do prefer Penelope and Cha Siyeon to be two different people so maybe the old nanny could be Siyeon or the royal family could give a personal bodyguard or teacher to Penelope which would be Siyeon but in the end it is up to the writer.