The crew of the vessel were on an exploratory mission when they encountered a magnetic storm in 2069 whereupon they were thrown off course and into galactic barrier. Exposure to its energy resulted gave powerful psychokinetic powers to one of the crew who was driven mad and believed himself to be a god due to his new found abilities. In order to survive and prevent this dangerous superhuman from harming other worlds, the ship was destroyed after the crew left in escape pods. They sent their ships disaster recorder out into space to warn others of the dangers of the Galactic barrier and had hoped that Earth would send a rescue team for them.
However, none came and the crews of the escape pods travelled for months near the proximity of the Galactic barrier giving them telepathic and psychokinetic abilities. These were not on the same level Geirrod Agnarsson and neither did they develop a god complex. By 2070, after their exposure to the energy of the Galactic barrier, the crew of the SS Valiant made planet fall on a class M world. Once landing, they decided to develop their own colony which they based on the works of a French architect after the Third World War which was called Magnia.
Years of seeing no contact from Earth since their vessels destruction led to the Magnians to develop their own society separate from Humanity to the point that they saw themselves as a separate species and culture. They were able to develop technology such as shields by themselves but never developed others such as the Transporter.
The location of their new homeworld meant that they fell prey to some of the Kelvan forces and later to the Nuyyad who discovered information relating to the United Federation of Planets. In order to conquer this foe, they decided that they needed to learn more and found the link between the Magnians and the Humans of the Federation. After raiding Magnia, the Nuyyad forced two of its colonists to attempt to bring Federation help as part of the trap. This led to First contact between the Federation and the Magnians who worked together to combat the Nuyyad threat which they managed to defeat. Once this was accomplished, it was the recommendation of Captain Jean-Luc Picard that Magnia remain a closely guarded secret of the Federation in order to prevent others from abusing the psychokinetic abilities of its inhabitants.
Magnians generally appeared as normal Humans with the major differences lying within their brains which were highly developed and provided them with a range of psychokinetic as well as telepathic abilities. These were finely tuned enough for them to manipulate their environment and even use their telekinetic powers to perform surgery.