The Scourge of Rock a.k.a. "The Beast" is the main antagonist of Guitar Hero: Warriors of Rock. You face him in the final chapter of the game, The Battle With the Beast. After beating the Quest mode and unlocking the ability to play with the Demigod of Rock, your band will play on the back of The Beast when performing in the 11th venue. The Beast appears in the game as a giant metal robot, with a stage replacing the area where it's head should be. On it's left hand it spotlight-like claw, from this it fires blue beams of energy that it uses to defeat the Demigod of Rock.
In Guitar Hero: Warriors of Rock, The Beast attacks the Demigod of Rock when he goes into his mortal form to perfect his sound. After defeating him in battle, he imprisons him in granite and casts his legendary guitar away.
In Quest Mode, you play as all the characters in order to unlock their Warrior Modes, get the guitar, and help release the Demigod of Rock from his stone prison so he can finish The Beast. You play the first two songs, "Holy Wars... The Punishment Due" and "This Day We Fight!" in order to weaken him and to release the Demigod. "Sudden Death" is played to empower the Demigod of Rock while he battles to The Beast; the battle ending with the Demigod slashing his guitar into The Beasts head.