She, the Ultimate Weapon (2002)

Chise is a small, shy and clumsy high school student who managed to work up the courage to ask Shuji, a tall, confident and athletic boy in her class, to be her boyfriend. The two make a cute couple, but their lives as they know them are thrown into disarray when war begins to tear Japan apart. Even more horrifying, Chise is taken by an unknown group, and her body is transformed into the military's ultimate weapon. With the knowledge of what his girlfriend has become, Shuji struggles to hold onto the Chise he loves, even as the military uses her for their battles and the rest of his friends are also pulled into the growing conflict. Meanwhile, Chise struggles to hold onto her humanity, fearful that herself as a weapon may one day overwhelm and destroy herself as a human.