Sunny is a native of Nia and a member of the Jackers, distinctive for her small red horns and red-tipped tail. (As a Nian, she does not naturally possess either. Artificial tails are a fashion accessory popular among younger Nians, and Sunny seems to be fairly image-conscious despite her longings for junk food.) The younger sister of Sandy (at around twenty-one), she is impulsive and somewhat naive, and has a fairly patchy understanding of history limited to a few key trends and concepts. She seems to consider herself to be coming along with the Jackers for the ride, rather than being on any prearranged mission in the past, and does not seem to know exactly why they are there, although she refers to Sandy's mission as an "evil plan".

Via a false display of knowledge, Sunny has managed to encourage Kokiro to consciously take instructions from her instead of from Pippin, although this imprinting does not seem to have affected Kokiro's obedience to programming commands.