The only time "too many characters" occurs is when too many of them begin to function the same, and the story fails to properly focus on them all. While admittedly the story could focus exceptionally well on two separate characters that are both "fighters" or "knights" or whathaveyou; there's no reason for them to have the same stats and/or skills, even if they were twins.
Generally, character stats and skills should reflect the character as an individual, and not be based off a generic preset list. As such, so long as the story CAN focus on a hundred characters at once, they should all easily be unique if you put that much effort on the cover.
And if you can't, sometimes one character is enough.
This post has been edited by ZarroTsu: Nov 28 2012, 07:17 AM