^ Sitri is not Rhea's clone. The details of her birth, for lack of a better word, aren't clear, but Rhea says that she created a body to put Sothis' Crest Stone in, hoping that would resurrect her. What creating a body entails isn't stated, but Sitri was very much her own person, and while Rhea did care about her a lot, their relationship wasn't one of parent and child. While Rhea hoped that Sothis could be resurrected through Byleth, it's important to remember that by the end of Silver Snow Rhea sees Byleth as her own person.