Kimiko Kujo

K whose real name is Kimiko Kujo is one of the letters of Wammy's House in L: Change The WorLd, who went down a dark path and became part of a bioterrorist organization which plans to "cleanse" the world of its excess population by a deadly virus.

She is one of the letters who went evil much like Beyond Birthday. However, unlike Beyond, Kimiko is turned back to the right path by L, as one of his last acts.

She is not in the anime or manga she is only in the film L: Change the WorLd