Plainbow is the akumatized form of Kuki Sanban.
Powers:[]
Able to send out beams form her oversized sleeves that drain all colour from anything and anyone they hit, turning it black and white. She is also able to fly and spin to create a colour-draining tornado.
Appearance:[]
Kuki's hair becomes half-white, like Cruella de Vil's and Princess Ivy's. Her Rainbow Monkey doll turns to a monochrome version of itself, which rides on her back, and her sweater changes to black and white stripes. Her shoes remain the same. She also gains a black eye mask.