Colonel Shikishima is a major supporting character of the AKIRA franchise. He is the military leader of Neo-Tokyo, who is usually called by his rank. He spends most of his time trying to keep Neo-Tokyo's corrupt government in line, while also watching over the Espers.
The Colonel is a serious man who is never seen smiling once. While he appears as a tyrannical figure, he is deeply concerned for Neo-Tokyo and, as a military leader and soldier, always considers the risks in his decisions. He also holds great contempt for Neo-Tokyo and even calls the city " a garbage heap made up of hedonistic fools", yet he still tries to make it better because, in his words, it's what a soldier would do. He isn't held in very high regard by his fellow political leaders, who see him as responsible for Neo-Tokyo's squalid state and blame him for draining the state's funds in favor of taking care of the Espers.
The Colonel holds scientific theory in disbelief and refers to scientists as "romantics". He scoffs at Dr. Onishi's theory of psychic powers being the next stage of evolution, though he muses at one point that humans weren't meant to meddle with natural evolution. Later, when the Colonel visits Akira's cryogenic chamber underneath Neo-Tokyo's Olympic Stadium, he criticizes the Japanese government for trying to hide what they created with their secret psychic experiments, referring to Akira as "Pandora's box".
While the Colonel sees psychic powers as something to be of use for the greater good, he is deeply disturbed by the coming of another Akira. When Tetsuo Shima, a young Capsule gang member, is shown to have similar psychic growth patterns as Akira's, the Colonel tries to have him killed to prevent Tetsuo from becoming another Akira, even actively hunting him down when Tetsuo goes on a violent rampage.
Not much is known about the Colonel, but he was born in the original Tokyo, sometime before it was destroyed by an accidental psychic explosion created by the psychic child Akira. Judging from his military rank and prestige, he presumably fought as a soldier in World War III before helping found and build Neo-Tokyo.
After Takashi was kidnapped by anti-government resistance members who mistook him for Akira, the Colonel tries to track him down, with the Esper Masaru aiding him. Using Masaru's powers of clairvoyance, the Colonel finds Takashi on the highway road Route 5 in the old Tokyo, where the boy was involved in the motorcycle accident of Tetsuo Shima, a young Capsule gang member. After successfully retrieving Takashi, the Colonel has his men arrest the Capsules and bring Tetsuo to a hospital while he brings Takashi and Masaru back to the Nursery.