A very surprising manga series that's in your face and rude as heck. As if "Evangelion" and "Akira" had a baby, and was raised with a steady diet of "Platoon", "Apocalypse Now", "Hurt Locker" and "Full Metal Jacket".
In the distant future, where humanity is living in an alternate dimension, a civil war erupts between the migrants and the Earth Forces in their new land. Fighting this battle are pilots manning 18-meter tall "high school girls" made of flesh and metal called "assault girls". The pilots integrate their will into the machines, therefore driving them, but the assault girls have their own behavior and quirks akin to a real, typical high school girl.
For a sci-fi series, it doesn't really explain the hows and whys behind the 'assault girls', but this actually prevents any distraction from the horror and grittiness that is going on in the moment. It does make me wonder, what is the advantage of having flesh and metal fighting robots who act like high school girls, chatting away in their cellphones, yapping about cuteness and fashion, and having them eat giant versions of food, and have normal body functions such as defecating and having menstruation. Aside for that, its a hell of a PTSD ridden ride along with the Hyena unit, as they search for their prey in the middle of a hellish war torn reality.