Mako (マコ) and Miko (ミコ), they were designed by Oruka Irukawa and were intended to be the anime counterparts of Katia Löfgren and Dinah Nah, who were the original singers for Caramell.
They are only featured on the albums "Uu-Uu-Uma-Uma(゜∀゜) SPEED Album" and the "Uu-Uu-Uma Uma" album pictured on the right. They were made solely for the Japanese Caramelldansen campaign that Exit Tunes had started along side Remixed Remixed records and the Caramella Girls.
Important note that Miko and Vera from the Caramella Girls are completely separate characters.