Saikano: the last love song on this little planet (2006)

Based on the Best Selling Anime Series "SAIKANO" Shy coed Chise (played by Aki Maeda from Battle Royale) is madly in love with high school athlete Shuji. The two share a bond which only intensifies when war breaks out in futuristic Japan. But Chise has a secret that - if revealed - would not only destroy her relationship but would also put her life at risk. Chise is not an ordinary teenage girl, she is actually the ultimate weapon of mass destruction, a genetically engineered cyborg built specifically for extreme military use. When she goes into battle, Chise strikes fear in everyone around her, including her own troops. Her boyfriend must never know.