She, the Ultimate Weapon (2002) IMDb
There’s a war going on. A big one. It isn’t evidently nuclear, the causes are unexplained and as it turns out, the tagline is almost literally true. A fairly normal guy lives on hitherto peaceful Hokkaido. When the first airstrike hits their city, the thing zipping through the sky and mowing down bombers with a Vulcan turns out to be his timid, clumsy girlfriend. This is the story of their relationship, with various effective human tragedies occurring in connection to it.
Wartime tragic romance with an isolated but remarkably intrusive element of hypertechnology. Okada Toshio of Gainax fame described it as “the definitive sekai-kei” in Little Boy: The Arts of Japan’s Exploding Subculture (2005), that being a genre wherein the fate of the world and one’s private feelings are strongly linked.
The super-weapon identity could have been handled a lot worse, but also a lot better. When the girl is worried, perfectly ordinary missiles pop out of her back. You never find out why there’s a war, why the war destroys the planet or why the girl becomes a weapon. The major premises thus go unexplored, which I don’t think is justified past episode 9 or 10, when the painful personal stuff is basically over. It gets melodramatic. The series, which began as a manga, has also been done as tokusatsu.
References here: Violet Evergarden (2018).