She appears in two time settings, once during Yukiteru's flashbacks while in elementary school in chapter 13, and much later towards the end of the story in chapters 34 and 35.
She was well-liked by everyone in class, since she was open and outgoing, and seemingly cheerful most of the time. Etou liked Yukiteru a lot, and not so much Yuno, to the point of attempting to force those two apart. Etou eventually transferred to another school, because of Yuno's unforgiving grip on Yukiteru.
Throughout, she has long hair with long bangs framing her roundish face and a straight fringe in a "bowl-cut", and dark eyes.
During her older appearance, she is still slim and fairly short.
She briefly states she has a brother, who is unnamed and unseen in the series, no other siblings are known. Nothing is known about her parents.