Chidori is a C Genomer which means that she is also a descendant of a Tennyo. She's actually much much older than she looks, yes, you're right, she's already 16 years old. Chidori, like Aya has Tennyo powers, the main difference is, she can control her body and mind whenever she wants to become a tennyo or in other words, she can transform to a tennyo whenever she wants. She is in-love with Yuuhi at a wrong time. Unfortunately for her because Yuuhi loves Aya.