Hmm I don't like the whole premise of this show. Little girl assassins that are killing each other. Pfffff not my thing.
And I also do think that it's trying way too hard to be "badass". All this super evil grinning, everyone is oh so mentally twisted and a real bloodlust oozing psycho. It just feels really forced and too "in your face!"
What makes you think that this is not going the yuri route?
Cat fights with daggers,
And the genre is yuri.