Xam'd: Lost Memories (2008)

Xam'd: Lost Memories follows the story of Akiyuki, a teenage boy who lives on Sentan Island. When a mysterious woman gives him a power called Xam'd, he transforms into a powerful creature known as a Humanform. Akiyuki is forced to leave his peaceful life behind and goes on a dangerous adventure to uncover the truth about his existence and the secrets behind the war that has ravaged his world. Along the way, he encounters various friends and enemies, all while struggling to control his newfound powers.