NAKURU AKIZUKI / RUBY MOON SPOILER!

Nakuru appears as a wildly energetic new student at Toya and Yukito's high school and immediately develops a talent for showing up whenever Toya is about to have an important conversation. She is actually Ruby Moon, the moon-aligned guardian created by Eriol as a counterpart to Yue, and unlike Yukito she is fully aware of both identities. Nakuru's bubbly school persona is not a separate personality so much as Ruby Moon having an excellent time. Her repeated interference with Toya and Yukito becomes much less harmless once Yue's weakening condition makes Toya's magical power important.