[yuki_unmei]

This is how Delirium-Zer0 explained it some time ago:

The origin of the nickname Chon-san is, yes, from ZIN's blog. During the making of the "Days" PV, he put up a photo of Ayu on the set (it was very dark though and you couldn't really tell who it was), and ZIN simply called this person "Chon-chan" because they kinda looked like they had a "chonmage" (the japanese word for top-knot) in their hair. Ayu revealed in her blog later that day that "Chon-chan" was her, and the nickname has since evolved into "Chon-san" and "Chon-mama."

The ninja thing is that Ayu used to sign off her posts with "Doron" or some variation of it, like "dorororororo~n". "Doron" means "slipping away unnoticed" or "silently disappearing," but ayu always said it so cutely that I translated the word as "Ninja vanish!" because honestly, that's totally what she'd have said if the entry was in english.

The Ninja/chonchan confusion comes from one particular entry in which ayu said "Dorochon" instead of "Dorororon" or anything, so she worked her "Chonchan" nickname into the "ninja vanish" phrase. For that entry, I had to translate it as "Nin-chon vanish!" and I put an explanation for it at the bottom of the entry.

In another thread, someone once asked about the "Chon-chan" nickname, and the only TA blog translation that one member could find with an explanation was unfortunately THAT one, but I was explaining "Nin-chon vanish," not "Chon-chan" or "chon-san", so that created confusion.

But THIS POST RIGHT HERE is the accurate explanation for both. XD

But now Ayu uses "nan" at the end of it, which i don't think has been explained at all..