Cutiepies who Save the World

Super cute sister and brother got transported to the magic world to save mankind?! Down in the depths of the parallel world outside of Earth, there were twelve magic seals sealing away ancient demons. One day, the twelve magic fairies guarding the seals were trapped and badly hurt by the evil vassal king. The king even cursed the fairies and turned them into babies with hardly any magic. Only by finding twelve children selected by fate could the fairies regain their powers and save the world. The story begins here...

(Source: Webcomics, edited)