Name the archetypal character who fits this description: a selfish loner who has noble motives, but is flawed in some way.

This type of character is usually a rebel with a cause. An example would be Snape who is one of the professors in Hogwarts. When he learned that Voldemort was planning to kill the Potters, he went to the Headmaster to save Lily only, and not James and Harry. Lily's death changed him and he became one of the most important characters of the series.

What is the story? i will you i just need the story