Runt

A runt is the underdog, usually a degrading name given to someone smaller and weaker by Jerk Jock who picks on him/her regurlarly. In Real Life however, a runt is merely an animal who is usually lastborn and it's parents don't give a flying flock about it, having not invested much in it in the first place.

In fiction and literature, they are often the good guys,and almost always come out on top and gain genuine respect from the people who once ignored them and grudging respect from the ones who tortured them to no end.

When they're not good however, and they don't do something heroic to gain respect, these characters often grow up slogging about in their hatred and frustration, and eventually become a Big Bad. And when they Become Big Bad's, they are usually the cruelest, heartless, most fiendish of them all, out for blood and ruling with an iron fist.

If they're not good or evil they're usuall the Moe Moe or Team Pet or both, abandoned on the streets then found and owned by the Hero.