Michiru and Kaoru were members of the Dark Fall. They worked as a pair, and they were originally told to guard the spring of the sky that the Dark Fall had taken. But they went to earth on their own to spy on the PreCure. It seems that they have some power related to the wind.

After confronting Saki and Mai in the forest, Michiru and Kaoru posed as junior high students and went to their class as transfer students. They didn't know much about human school life, but they picked things up very fast, and excelled at studies and sports.

At first Michiru and Kaoru fought against the PreCure, but at the end they became friends. So Akudaikaan killed them. Their bodies were sent to the bottom of the ocean in Dark Fall. But they got resurrected by Queen Fiilia's power, and they fought along with the PreCure against the Dark Fall and Gooyaan.