Guitar Hero is a series of video games originally created by Harmonix but later transferred to Activision. Due to the numerous amount of games in the series, there are different careers progression systems and different bonus songs for each game.
For the first two games, the story is simple, you play gigs and become a rock star.
Starting with Guitar Hero 3: Legends of Rock, you are a guitarist who works his way up to the top, guitar battling celebrities and dueling with the devil himself.
For Guitar Hero: Aerosmith, Metallica, and Van Halen, you are a guitarist who performs with his band in order to open for Aerosmith.
For Guitar Hero: World Tour, Smash Hits, 5, and Band Hero, you and your band work your way to the top to become a successful music group.
In Guitar Hero: Warriors of Rock, the Demigod of Rock is set in stone, and rockers from several time periods are summoned in order to save him from his rocky tomb and destroy the beast that defeated him.