Lilian York is Athy's main caregiver, as well as being the head maid. Despite being aware of the Ruby Palace incident, she still volunteers to be Athy's nanny due to an admiration of Diana's free spirit. The two share a close bond in both the book "The Lovely Princess" and the manhwa itself.

Spoiler

Their bond is so strong that Lilian died while protecting Athanasia from her execution.

Lilian is shown to be a loyal and affectionate caretaker, with Athanasia reciprocating those feelings. (Source: Who Made Me Princess Wikia)