Yotsuba can best be described as chirpy, cheerful, and full of curiosity, as she wants to know all of her brother's secrets. This little detective is never anywhere without her magnifying glass, as she's always checking things. Her signature phrase"checki" always comes up when she's investigating something very interesting.

Yotsuba comes from England and is one of the three new sisters that made her first appearance in 2000 in Dengeki G's magazine and the first Sister Princess game.

In Sister Princess RePure, she brings up an interesting point about how much all of them really know about their brother. She teams with Rinrin in order to find out more about him, and like the rest of her sisters, wishes to become closer to him.