Mozu and Kiwi, also known as the Square Sisters (スクエアシスターズ) due to their square-like hairstyle, are very loyal to Franky, and go with him everywhere. Mozu is the sister with the yellow bikini top, yellow slacks, and straight edged hair, while Kiwi is the sister with the red top, red bikini bottom, and curly edged hair. They have a tendency to mimic his reactions. They often walk sideways in high winds, due to the fact that otherwise their hairstyles would cause them to be blown back. During battles, they fight with samurai swords, but are not especially powerful, as Franky and Kalifa easily subdued them. They both also have a tendency to add “Waina” too all their sentences. They’ve done that ever since they were young.

(Source: One Piece Wiki)