People who smash face and take names, fighters are an odd strain of life who embody humanity's unconscious urge to beat the crap out of everybody for various reasons. Experts such as biologists, sociologists, and housewives show contempt towards this species due to their aggressive and unruly behaviour, but have learned to respect fighters while studying them should these experts suffer from a good backbreaking.
Fighters are intriguing in that like Pokemon, they come in a variety of shapes and sizes, practice differing styles of martial arts and happen to be in the fighting business for their own personal reasons. Some intend to perfect their fighting styles; some are in it for the money; some are on a quest to save or avenge a close friend or relative; a few are off to conquer the world, while others just want to have a good time.
Given these criteria, everyone has the potential to be fighters, regardless of age, competence, and sexuality. Even a total goof-off who can perform decent attacks half the time can be a good fighter. it's all a matter of how these people dodge and parry while proceeding to knock their opponent's block off.