[Keroko]

Originally Posted by Justin_Brett

She has cat ears because

Spoiler:

there was apparently a whole race of cat people in Ancient Belka for whatever reason. Which seems a bit odd and out of place since the series has never really had races besides straight human, but whatever.

Actually, there was a cat-eared person in StrikerS, on the airport when Signum went to pick up Erio. We all just assumed it was a familiar (which it probably was at the time, but retcons, ho!)