Raku-chan is the main character in NNSG.
Raku-chan has a green bob haircut and purple eyes. Her ears are a lighter gray than her tail is, and she is also recognizable as being the only main character who has a large bust. (Sometimes, it seems that her breasts are the only things shaded on her character.) Since she was referred to as "young" by her best friend Koneko and her features are much more childish than that of the other characters, we can also assume that she's likely the youngest character in the fanime and that her age is probably in the lower teens. Raku also wears a blue t-shirt and a pink skirt during a majority of the show, and is often drawn with "blushies" on her cheeks.
Raku-chan acts young for her age, which is noticeable through her reactions. Though she cries often throughout the series, she is usually very happy and thankful for her friends, Hitoshi and Koneko. She often wants to repay their kindness as well, but usually lacks the means to do so. She also wishes that everyone didn't have to dote on her, and that she could be more helpful to her friends.
Raku is also very innocent and friendly. She sometimes doesn't see the immediate consequences for her actions, which can lead her into trouble, as seen in the fourth episode of Nyan~ Neko Sugar Girls.