Bibisco is an open source application for writing novels.

With bibisco you can organize chapters and scenes, manage revisions, export
novel in pdf or rtf, and write with a fully featured text editor.

You can create a novel structure, define premise, fabula, narrative strands and
settings: geographic, temporal and social context.

And, most of all, with bibisco you can know everything about your characters.
Because your novel works only if its characters are believable, that is when
you understand their human nature's complexity.