Ignis

A dragon of Fire. A dragon of Earth. A dragon of Water. A dragon of Air. Together these four form the Dragons of Creation. The lives of Agni and Zephyr are turned upside down when they are attacked by a murderous bus-sized crow. They are rescued by a magical girl, Cassiopeia, who tells them that they are very important people. Well, actually, more like very important dragons. Apparently, the two of them are Soul Keepers, humans who have souls of dragons in them, with some of the most powerful dragons to ever live bonded to them. Agni, Zephyr, and two other Soul Keepers, Triton and Geb, are thrown into a new reality, filled with dragons and danger, as they race against the clock to retrieve the soul orb of Ignis, the Dragon of Fire. Book 1 in the Dragons of Creation series.