A main character who is the brother or sister of someone who seems to overshadow them in every way. They have the skills, looks, friends, their parents favor them, etc. But the jealous and bitter brother or sister is the main character. Even better if its in a action/adventure setting and the favored sibling turns out to be bad and the ignored main character becomes a hero. Some romance is a plus but not necessary. I would prefer a angry and mean main character who hides his/her insecurity to a openly gloomy one.

http://tvtropes.org/pmwiki/pmwiki.php/Main/CainAndAbel <--Like that but I want the "bad" one to turn out as the main character and hero.

Seigi no Mikata sort of fits I guess.