The Hidden City is one of the successors to the Old World destroyed by the Coming of the Azure Flames, and like the others it had ties to the twin conspiracies that foolishly destroyed that world in their hubris. In this case, the founder of the Hidden City was a programmer, engineer, and occultist by the name of Roger M. Ire. Inspired by Disney's Tron as a boy, he pursued programming and engineering as he got older; these lead him into philosophy as a sideline in university, which is also when he got into the occult and recruited to DARPA.
Once initiated into the Deep State, Ire would gain access to secret information Disney used to inform Tron, going on to realize the concept and figure out how to make real the postulated digitization of real matter into a digital construct. In doing so, he pushed for and contributed to several patent-making advances in computer and network hardwarve, software, and firmware; these patents allowed him a passive and clean income that freed him from needing to maintain a cover identity as most do.
The occultist side of the twin conspiracies saw the potential in his work, and gave him the cover he needed to get out of the known hubs of IT and engineering in favor of hiding in plain site in Minneapolis. He hid his work under the guise of medical technology research, gaining access to power and network resources needed for his laboratory; in this lab, he did what--again, through Disney--was fictionalized in Tron: Legacy: the creation of a virtual city-state that people could freely transit to and from.
But Roger Ire, by now, was no naive idealist like fictional Kevin Flynn. His studies of the occult led him to conclude that programming was so much like sorcery that they had to be related somehow, and his presence around medical research of all sorts lead him to conclude that DNA has to be some form of code--therefore, a symbol representing a thing that has effects in reality, which therefore can be manipulated to make effects that he desired. He concluded that the solutions to several long-standing known issues of Mankind could at last be solved, permanently, and drew up a few plans to do so.
That was when his contacts in the occultist conspiracy also informed him of the Grand Ritual plan. He--like Solador's Archmage--saw through immediately as hubris destined to fail and bring ruin, and he moved to execute a survival plan. He took a big gamble, as he suspected that the Minneapolis area was a convergence of hidden energy, and devised devices that he--at the time--did not fully understand to tap into it to use as emergency power to keep the Hidden City online.
When the Azure Flames hit, he sealed the lab to all physical access and put the taps into place before taking one last trip through the transit portal to the Hidden City and hoped for the best. Instead of facing oblivion, he found himself faced with a crisis of power surging into the system; he was right about the power source, but had no idea that it had been dormant and came to live in the wake of 90% of Mankind being either nuked to ashes or consumed in the waves of blue-white flames that followed. The Hidden City, then a small thing, grew into a gleaming metropolis in the blink of an eye as Roger struggles to use what threatened to overwhelm him in maddening sequences of program resolution and iteration from the inside.
To cope with the surges, Roger connected to the Internet knowing that the Deep State installations meant for Continuity of Government would be online, connected, and hardened enough to stay up. With the power at his command, he got into the local systems and usurped their automated tools so that he installed and integrated additional transit portals throughout the world and then secured these facilities to his command alone. It was during this crisis that Roger became aware of what went on outside in realspace, becoming aware of The Necromancer and the undead horde he controlled.
At this moment, Roger had a sudden thought: "This is my mission, to reformat the whole of Creation and bring it into the perfect system."
The Hidden City would, over the years, grow both in virtual and real population. During the time of The Necromancer is when Roger--now known as The First Founder--started recruiting real people to operate in realspace as his agents. (N.B.: This is a big part of the Solador story; Roger sends an agent to overthrow The Archmage.) It is here that Roger, and his growing body of disciples, turn the power of The Hidden City to making super-solders.
Roger and his disciples created their first model based on a need for deniability and concealment, but when action became necessary great power could be put to hand. As this first cadre was a small one, a focus on quality in power to make competency in acumen was the goal and (as all of them were survivors of the Old World) they used a Japanese model as their basis: The masked heroes of the tokukatsu genre and their animated counterparts.
They then blended this model with an older American one, that of DC's Captain Marvel (a.k.a. "Shazam"), giving each agent a secure passcode keyed to their unique genetic code- a sample of which Roger kept on file as a security failsafe. Later iterations and revisions would refine this concept until there was a clear gradation of power, granted by demonstrated quality of character as well as loyalty to The Hidden City (and, by extension, to Roger), and Roger decided to foster this via deliberate generational eugenics improvement. The goal? To create the ideal agent of the City and its interests as the Guardians of Civilization.
And, unnoticed by most, this was when Roger's fall into hubris became complete.