performing on stage as the player attempts a song, but otherwise has no effect on the gameplay. A certain number of characters are available at the start of the game, but the player must spend in-game money earned by successful performances to unlock other characters. Many of the characters reappear throughout the series, with the character roster changing as new characters are added or removed. Standby characters that have appeared in nearly all the games include the metalhead Axel Steel, extreme/Viking/thrash metalhead Lars Ümlaut, punk rocker Johnny Napalm, alternative rocker Judy Nails, and hard rocker Casey Lynch. The developers utilized these characters in more detail within Warriors of Rock, where each was given a unique setlist and venue based on their musical style, as well as a unique power within the game's Quest mode. Several games in the series feature caricatures of celebrity artists, such as Slash, Tom Morello and Bret Michaels in Guitar Hero III, Ozzy Osbourne and Jimi Hendrix in World Tour, Kurt Cobain in Guitar Hero 5, and Taylor Swift and the band No Doubt in Band Hero. The band-specific games, Aerosmith, Metallica, and Van Halen also feature the members of the respective bands. However, in late 2009, both Courtney Love and the members of No Doubt sought legal action against Activision for the misuse of their in-game characters singing or performing songs by other artists, which the musicians believe fell outside of their contract. The ability for the players to create their own avatars was added in Guitar Hero World Tour, and was based on Neversoft's existing character creation tools from the Tony Hawk series. Later games on the Xbox 360 and Wii allowed players to use the respective console's avatars as members of the band. In addition to unlocking characters, in-game money can be used to buy clothing, accessories and instruments that they are seen playing with. The guitars can also be customized with special finishes purchasable through the in-game store. Guitar Hero World Tour includes the ability to fully customize any component of the guitar. The in-game store in the series is also used to unlock bonus songs or special videos with interviews about the game or with the artists involved. Soundtracks Most of the games in the Guitar Hero series feature a selection of songs ranging from the 1960s to present day rock music from both highly successful artists and bands and independent