The Seven Samurai of Anime
This was a multi-author project about an invasion of Earth by body-stealing space aliens. It's apparently been abandoned, but my parts featuring Kodachi should stand more or less on their own. Just don't blame me for the premise. :)

Kodachi intro
Kodachi backstory

Comment: A lot of other fanfics have had Kodachi locked up in an insane asylum. It was amusing to turn this around, to show her in such a facility but have it turn out that she's locked up unfairly and what sounded like an insane delusion was actually true.