Leviathan: The Last Defense.

The fantasy world of Aquafall is abound with water and greenery, and populated by dragons and fairies. Meteorites of evil creatures threaten all living things on the planet. The fairy Syrup assembles the Aquafall Defense Force, with three girls of the dragon clans as recruits. The story follows Syrup and the dragon girls Leviathan, Bahamut, and Jörmungandr as they work together to battle enemies and grow up.