), a fighting competition held every ten years. During the course of the story, more background about the setting of Battle Angel Alita that was not disclosed in the prior series is revealed, such as how the Earth emerged from a cataclysmic impact winter that wiped out most of the population.
), a martial arts tournament held every decade. Throughout the narrative, more background information about the setting of Battle Angel Alita is unveiled, including how the Earth recovered from a devastating impact winter that decimated most of its population.