Okou was one of the members of the Ooedo Chakichaki Girls/Goodenough Girls and was the Edo-era counterpart of Buttercup.
She appeared in episode 51 along with Omiya and Momo. She shares the same personality as Buttercup, her weapon is a big wooden hammer. she wears a green Kimono dress after transforming. Before her first present appearance, She also had a brief appearance in What's with Him? (Episode 30), where she is seen fighting off Him for the first time and is mentioned by Professor Utonium in that she was a part of the Goodenough Girls. She looks like Buttercup, except that she has tidier hair.