The Black Jewel is an evil treasure that Wario collected, in the game, Wario World. It kicked Wario out of his castle, turned all his treasures into monsters, and turned his castle into a strange world. Wario had to embark on a quest to get back his castle and treasures. The Black Jewel only awoke on an evening were a red moon rose. It wiped out all civilization long ago and returned. But little did The Black Jewel know that Wario had beaten every boss of the other worlds and was coming for it. Then after finishing The Black Jewel, Wario reclaimed his castle and treasures and lived happilly ever after.