The main antagonist of the film '. Dr Kimiko Kujo was a scientist who led a bioterrorist group that strives to use a virus to wipe out most of the mankind to create a new world, believing that the world was corrupt due to humanity's countless acts of undoing. Going by the alias K, Kujo was a former student of Watari, and was known to L. It was mentioned by L that Watari used to be proud of her, possibly due to her intelligence and academic achievements, for which this also implied that her extreme methods and disregard for humanity had led to Watari putting a possible end to their relationship, as hinted by some parts of the movie. In the movie, prior to the murder of Dr Nikaido, Kujo had a close relationship with Maki, Dr Nikaido's daughter.