Rayearth's Description

When asked to list all characters in MKR, Sierra gets missed out most of the time, partly since she wasn't in the Manga, and partly because she's just nearly exactly the same as Presia that people forgot they were actually two different people. The Knights were never told of Sierra's true identity, they were told she was Presia, and Hikaru was in tears when she met Sierra. Sierra and Presia are twin sisters, the only thing that could tell them apart is a birthmark on Sierra which Presia didn't have. However, Alcyone somehow managed to figure out she wasn't Presia the first time they met.

It seems that Sierra loves Clef too. This just makes it even more harder for anybody to know she wasn't Presia, but Clef knew from the start. In the first season, there were only hints (although very obvious hints) about Presia loving Clef, but in the second season, Sierra openly declared her love for Clef, although she said it in front Alcyone and only managed to say "that person" instead of Clef's name. Sierra is also a Pharle in Cefiro, her skills are nearly as good as her sister's - she managed to repair Hikaru's Escudo sword after Nova broke it.

Facts about Sierra