Noa-senpai wa Tomodachi. - Ch. 13 - Yakiniku with Negiemon

[sarusa]

Someone already got the 久々, so yeah -ko is a common suffix for girls. When it didn't mean 'child', it means 'girl'. Lots of girls are actually named -ko, like Aiko or Kyouko or Yuuko. So if you want to make a nickname an annoying girl like Negi might use there's the obvious Noa-chan, but then Noacchi, Noapi, Noaemon (only if really trying to be obnoxious) or Noa-ko.