Two manga adaptations of the Fafner in the Azure story have been released and they both share the same title as the TV series.
The first one is illustrated by Mikami Akitsu. It ran in Dengeki Daioh magazine from July 4, 2004 to December 26, 2004 and was collected into two tankōbon volumes by MediaWorks. Digital Manga Publishing licensed this manga for release in North America and published the volumes on July 7, 2010 and April 30, 2011.
The second one is illustrated by Tomomi Matsushita. It’s currently being serialized in Kodansha’s Monthly Shōnen Sirius magazine. As of November 2015, it has been collected into three tankōbon volumes.
Plot Summary: Tatsumiyajima is the central island in the middle of a small cluster of islands, in a sleepy backwater of the Japanese isles. Not much happens there, and the island’s young people go to school knowing that their lives are likely to remain peaceful and undisturbed. Or so they have been taught…but the truth is different. The fate of mankind is on the line, and Tatsumiyajima is the last line of defense against a hostile and incomprehensible enemy. At the center of it all, fighting for Humanity’s continued existence, is the giant robot Fafner, the dragon that guards this final treasure of mankind.