A half-British, half-Japanese girl who was Alice's friend back in England. She also comes to Japan and enrolls in Shinobu's school.
Karen generally is a very energetic girl (even more so than Youko). She is very outgoing and not afraid to show her emotions.
Karen has mentioned on multiple occasions that she "really really really loves" Shinobu (大大大好き!), which makes Alice jealous sometimes. She gets along with everybody in her class, even to the point where they would give her lots of food if she ever forgot her lunch. It has been noted that Karen doesn't gain weight despite consuming lots of food.
She calls Aya, "Ayaya", because of a small misunderstanding when they first met.