So now that leaves the question, "Who is this guest artist named Utaroku and do they have a Pixiv account or Danbooru tag?"

I think he is six_song

his pixiv account is: http://www.pixiv.net/member.php?id=34446

lily_white said:
So now that leaves the question, "Who is this guest artist named Utaroku and do they have a Pixiv account or Danbooru tag?"

Going to his site link and clicking the "About" link reveals a Pixiv link at the bottom of his profile. His Pixiv user name is still Utaroku, but directly viewing one of his images shows his registered ID as "uta6". Neither turns up in a tag search on Danbooru.

So the answers, in order are: An artist friend of Bkub's, yes, and no.

act your age yukari.

Psycho_calibur said:
act your age yukari.

17 instead of 16?