Gary Mitchell a 23rd century Human, born on stardate 1087.7 in the city of Eldman, who later served as a Starfleet officer.

A medical study into his family history found that several members of his family, and distant ancestors going back six generations on his mother's side, had esper-oriented abilities. One of his ancestors had an interest in "spiritual readings." His Esper rating (091), Aperception quotient (20/104), Duke-Heidelburg quotient (261), and general knowledge quotient (679532-112) were well above average.

Growing up

He was better at "guessing games" than chance would allow. He also had a grade school interest in magic tricks.

Early career

Mitchell was an Academy friend of James T. Kirk, stemming back to the time then-lieutenant Kirk was serving as an instructor and Mitchell was a first-year cadet. That year, Mitchell aimed a "little blonde lab technician" towards Kirk as a means to distract his rigid instructor, and whom Kirk, in turn, almost married.

Later they encountered sentient rodent creatures on Dimorus that threw poisoned darts. Mitchell took one of the darts meant for Kirk and almost died from it.

They also spent a wild shore leave together on Deneb IV. Whilst there Mitchell showed marked ability in sensing the telepathy of the inhabitants.

Encounter with galactic barrier

In 2265, he was a lieutenant commander assigned as the helmsman aboard the USS Enterprise. The Enterprise discovered the flight recorder of the SS Valiant, a starship missing for almost 200 years. Examining it, and exploring the Valiant's last known position, the Enterprise penetrated the galactic barrier, an event that proved disastrous for Mitchell.

Mitchell was briefly stunned by direct contact with the strange energies of the barrier, but he recovered quickly. As he recovered he began to display a widening array of psionic abilities, including, but probably not limited to:
* Hypercognition
* Conscious regulation of autonomic reflexes
* Telepathy
* Extrasensory perception of various kinds, including clairvoyance, clairaudience, and clairoratory
* Telekinesis
* The ability to harm other organisms using directed energy
* The ability to manipulate matter, including the instant materialization and dematerialization of both organisms and objects
* The ability to control energy, including invulnerability to phaser weapons

These abilities began to fundamentally alter Mitchell's personality: he became progressively more emotionally distant, cruel, ruthless, and convinced of his own magnificence. Worse, with the passage of time his abilities continued to grow stronger at a geometric rate. They were accompanied by only two physical manifestations: a curious silver light or glimmer that appeared in Mitchell's eyes, and a later accelerated graying of his hair, beginning at the temples and sideburns.

Damaged by the galactic barrier, the Enterprise limped to Delta Vega. By the time they reached that planet, Kirk was convinced that Mitchell was dangerous, and attempted to maroon him there. But before repairs were complete, Mitchell had grown too strong to be confined. He killed Lee Kelso and left Kirk and Spock stunned, and escaped into the hills around the lithium cracking station, taking another member of the crew, Dr. Elizabeth Dehner, with him.

Recovering, Kirk took a phaser rifle and set out in pursuit. He left orders for Spock: If Kirk had not contacted the ship in twelve hours, Spock was to leave with the Enterprise, and recommend Delta Vega be subjected to a lethal concentration of neutron radiation.

Mitchell, meanwhile, was using his power to establish a pleasant environment for himself, materializing trees and other objects. Sensing Kirk's approach, he sent Dr. Dehner to meet Kirk, where Kirk discovered that Dehner had undergone the same transformation. It took a little longer for her, perhaps because she didn't have quite as high an esper rating as Mitchell. Kirk attempted to appeal to her remaining humanity, and when this seemed to be working, a disappointed Mitchell appeared. Mitchell, at least in his own mind, had already transcended mere humanity.

Dr. Dehner had enough humanity left to be appalled at Mitchell's actions, and she used her new powers to attack him. At the cost of her own life, she weakened Mitchell long enough for Kirk to overpower him. Kirk knocked Mitchell into a hole Mitchell had prepared (ironically) as Kirk's grave. Using a phaser, Kirk collapsed the hillside on top of Mitchell, burying him beneath tons of rock and ending his threat forever.

In his log, Kirk recorded that Mitchell and Dehner both died in the line of duty, noting that neither one of them asked for what happened to them.