A god-like figure, who is the result of a series of military experiments.
History
Little is known about the past of Akira, beyond that he was incorporated into the military's psychic experiments around the age of 10 and did not mature physically beyond then. As he gained control over his powers he eventually caused a massive explosion that ignited World War III and destroyed all records of his creation.
Anime
In the anime film, Akira's was later dissected into many body parts and was subjected to every test known to modern science. Scientists were unable to find any information on his powers. His parts were cryogenically frozen and stored under the Olympic Stadium for research by future generations. He is restored by Tetsuo Shima and other children from the military experiments, and is involved in the destruction of Neo-Tokyo-- as well as the transfer of Shima to another universe, where he reigns as a god-like figure.
Manga
In the manga version, Akira was cryogenically frozen whole.