Xam'd Lost Memories (2008, Bones)
Sentan Island is caught in the middle of a warzone. Akiyuki looks like your everyday student rushing off to school when there is an air raid and the school bus he was on explodes. While trying to help a refugee he helped sneak onto the bus, he finds himself "Xam'd" - when a human is injected with a seed known as "Hiruko" transforming them...