SAIKANO: THE LAST LOVE SONG ON THIS LITTLE PLANET (Saishu Heiki Kanojo), by Shin Takahashi. First published in 2000, and first published in North America in 2004.
PLOT:
In a no-name town on Hokkaido, Shuji and Chise are trying to start a relationship. It doesn't go very well at first, as Shuji is taciturn and cross while Chise is apologetic and shy. Then Shuji discovers Chise's secret: she was chosen by the SDF to become The Ultimate Weapon. Progressively, more and more of her body is transformed into a terrible alien machine, used to fight against an unknown enemy. As this is happening, Shuji and Chise struggle to find a way to preserve their fledging love against forces far greater than their own.
