The character of Sunako is very self-conscious, and has a fairly bad self-image of herself. She frequently calls herself ugly, and never acknowledges herself as a beautiful person. Most of the time she can be found in dark spaces or areas that are believed to be haunted.
At the same time, the author shows that Sunako also has very strong convictions. This could range anywhere from defending her fellow characters to refusing to do anything she dislikes, such as dressing up. It is frequently shown in both the anime and manga, however, that Sunako has no problem compromising some values (i.e. dressing up) in order to further her own ends. Sunako's fascination with all things dark and morbid resembles that of the story's creator, albeit in a more extreme form.
A constant theme of Sunako's personality is her view of beautiful and ugly people. She sees herself as ugly, while viewing characters such as Kyohei or Noi as incredibly beautiful. Sunako's belief appears to be that while beautiful people can become ugly, ugly people can never become beautiful. In the manga Sunako often reacts violently to the presence of beauty, believing that ugly people such as her should stay in the darkness. However, the problems with Sunako's retreat from the world is that it limits her capacity for life, as well as keeping her from fairly viewing all that is around her. It can be suggested that by Sunako adopting such a severe viewpoint on "ugly" and "beautiful" people, she has become exactly the type of person that she despises. One such character similarity can be seen by comparing the person who dumped Sunako at the beginning of the manga, and Sunako herself assuming that Kyohei couldn't understand her due to his beauty.
