Akira

In 1988, Tokyo is destroyed in a single explosion and World War III begins. A new city called Neo-Tokyo is eventually built in its place, but by 2019, a year before the city is set to host the XXXII Olympic Games, the dystopian metropolis is gripped by anti-government terrorism and gang violence. One night, teen delinquent ShÅtarÅ Kaneda has his bÅsÅzoku gang, the Capsules, battle the Clowns, their rivals. During the fighting, Kaneda's best friend, Tetsuo Shima, crashes his motorcycle to avoid Takashi, an esper with psychic powers who fled from a secret government laboratory. Colonel Shikishima of the Japan Self-Defense Force, assisted by another esper called Masaru, escorts Takashi back to his home and hospitalizes Tetsuo. When Kaneda and his gang are interrogated, he encounters Kei, a member of the revolutionaries, and arranges her release along with the Capsules.
Shikishima and Doctor Ånishi discover that Tetsuo possesses psychic abilities similar to Akira, an esper who caused Tokyo's destruction. Meanwhile, Takashi's friend Kiyoko has visions of Neo-Tokyo's impending destruction, and Shikishima proposes killing Tetsuo to prevent this from happening. Fleeing from the hospital, Tetsuo steals Kaneda's motorcycle, accompanied by his girlfriend Kaori, but the Clowns attack them both; the Capsules stop the fight. Suffering severe migraines and hallucinations, Tetsuo is taken back to the hospital. During a terrorist attack, Kaneda rescues Kei from capture and joins the rebels when he overhears their plans to capture Tetsuo. At the hospital, the espers attempt to help Tetsuo bring forth his psychic powers by heightening his emotional distress, but fail. Tetsuo, enraged, attacks the hospital, intent on killing the espers. Kaneda, Kei and Shikishima attempt to stop Tetsuo's assault, but are unsuccessful. Learning Akira lies in cryonic storage next to the Olympic Stadium's construction ground in Old-Tokyo, Tetsuo escapes the hospital.
Aided telepathically by Kiyoko, Kei escapes along with Kaneda to prevent Tetsuo from releasing Akira. Meanwhile, Shikishima stages a coup d'Ã©tat in search of Tetsuo. Tetsuo ambushes Kaneda's friends Yamagata and Kai, killing the former in the process; Kaneda vows to avenge Yamagata. Meanwhile, Tetsuo attacks Neo-Tokyo, eventually arriving at Akira's cryogenic storage dewar in the stadium. He defeats Kei and exhumes Akira's remains, but soon realizes that Akira was dissected, frozen, and preserved for future studies. Kaneda battles Tetsuo and Shikishima uses a laser satellite in an attempt to kill Tetsuo but are unsuccessful. Tetsuo destroys the satellite and fits himself with a robotic arm.
At the Olympic Stadium, with Tetsuo in immense pain, Shikishima tells him that the espers' migraine-controlling drugs are to stunt the evolution of uncontrollable abilities. Tetsuo attempts to seek a cure for his mutation, but Shikishima stops him. Tetsuo's arm mutates and he attempts to kill Shikishima before Kaneda intervenes and attacks Tetsuo. Unable to control his powers, Tetsuo mutates into a gigantic writhing mass and he engulfs both Kaneda and Kaori, killing and assimilating the latter.
With Tetsuo having grown beyond the requirement of a coherent biological form, the espers awaken Akira. Manifesting himself from the canisters, Akira reunites with his friends and destroys Neo-Tokyo in a mirror of the destruction of Tokyo, dragging Tetsuo and Kaneda with it. As Tetsuo struggles against Akira's psychokinetic powers, the espers teleport Shikishima away from the stadium, and Takashi leaps into the explosion to rescue Kaneda. The other espers aid in the effort at the cost of being unable to return. In the explosion, Kaneda experiences Tetsuo's and the espers' childhood flashbacks, including how much Tetsuo trusted Kaneda and how the children were trained and altered before Tokyo's initial destruction.
The espers help Kaneda escape and inform him that Akira will be taking Tetsuo to safety; Kiyoko reveals that Kei has begun to develop psychic powers. After the explosion, Kaneda discovers that Kei and Kai have survived, and they drive off into Neo-Tokyo while Shikishima watches the sun rise over the city. Tetsuo comes into control of his powers, and he triggers a big bang in an alternate universe.

Question: Who does Kaneda try to prevent Tetsuo from releasing?
Answer: Akira