Xam'd: Lost Memories (2008)

On a tranquil island, chaos erupts as a terrorist assault shatters the peace. Caught in the turmoil, a young boy named Aiyuki undergoes a shocking transformation into a metal-encased warrior. This newfound strength, however, brings perilous challenges. Aiyuki embarks on a quest to harness his extraordinary abilities while grappling with the threat of being consumed by the very force that empowers him—a mesmerizing blend of rock, metal, and magic that could lead to his ruin if he fails to control it.