Tsukiyo Ooba
A second-year student who rarely shows up to art club, and has unkempt hair with long bangs which hang over and conceal her face (not to mention, obstruct her vision). These factors contribute to her apparent anonymity and forgettability, as other members of the art club often fail to recognize her, both facetiously and otherwise. She evidently specializes in oil painting and the cup-and-ball.
She appears in the background in various episodes of the animation, but is not introduced until the final episode.