While I definitely prefer "A Drive of Dragons" for the second title, I'm genuinely conflicted on the first. I love one-word titles, and I love the simplicity and strength of "Honor." You're right; it succinctly encapsulates what drives your MC. And possibly I'm a little sentimentally attached to it, since it was "Honor" when I first read it.

I voted for "Longsword" because it has the same one-word "punch" and because I think it is less generic and more attention-grabbing. And I think it ties in very well with the theme and action of the book. My one concern, thinking about it, is that "Honor" more readily implies "literary sci-fi" and not "actiony sci-fi." But then there *is* action and tension in the story, and it's not a lie to promise that.