Thread:Lord Hyōga/@comment-5126314-20140702020203

As ridiculous as it is, all the major yokai characters listed in the Inu-Yasha Profiles book have "Number (in human years)" under their age information. While the concept itself is kind of silly, it is information that comes directly from Rumiko Takahashi herself, supposedly, after perhaps being badly translated by VIZ.

I think it just means that they appear to be "15 in human years" or whathaveyou. I can even take some pictures of the pages where it says their age in human years, though I think that if you're already completely against it, seeing it in the profiles book won't persuade you otherwise. :P 