That monster on the right page seems to be Diablos from the Monster Hunter series, judging from the name and class. Probably not very important, but I'm changing the spelling anyway.
This reminds me the fact that Keine being a hakutaku is an acquired trait. And yet she has the surname 上白沢. Counting the possibility of changing her surname after she became a were-hakutaku out, I'm surprised I haven't seen doujinshi that try to explain this. I'm trying to make one.
An extremely respected youkai. There's even writing about it in the Book of Secrets.Suddenly... green... fluffy...Akyuuuuu!She isn't sick.FretFirst, calm down, please.Will she get better?My Book of Secreeets!WHADDYA MEAN "LOOK HERE"?Fret
PanicFuss
DitherWag
WagLook here!Hakutaku?Akyuuu~! Keine ... sniff T-Tail...horns... at night... sniffChanging on a full-moon night... that form...No mistake, she's a hakutaku.