[KID2NR]

Originally Posted by Vertiago

From the information I got, I don't know what the two girls really do. I'm guessing that their goal was to do something to Tama, but yeah, it didn't happen.

Now, onto the two girls:

Spoiler for The girls in the later chapters:

The blonde-haired girl with pigtails uses a shotgun as her weapon and usually always pops up upside down, but I forgot what her name was.

The black-haired girl with the spider emblem On her eyepatch uses threads connected to something as her weapon. I forgot what her name was, but it meant "black cherry".

The blonde-haired girl's name is Ekou, a Tenshou-sagari (a youkai that, as you said, appears upside-down), and the black-haired girl's name is Kurozakura, who is a Jorōgumo (spider-woman).

@NeurtralZero: It's Rinko, not Ringo.

BTW I got my hands on a pre-order copy of Volume 9 on Tuesday. If this keeps up, we can see Volume 10 up in February and we'll be caught up with the Japanese volumes. That is, if Volume 11 isn't announced yet.