Azuki

A student in the science camp's astrology class. Her cat ears and her tendency to talk about science fiction make her come across as strange, but she's a very friendly girl. She and her family used to live in Japan, but have recently moved to Europe.

Spoiler

She's actually a member of a race known as "star humans", descendants of humanity who live in space under the Ancients' care and secretly monitor the "savage" humans on earth.