Demon's Fair (officially designated D-4358) is a fringe world bearing at least two sources of psi-enhancing terrazine gas. The Tal'darim settled the world, exploiting one source until it ran out. They left, never exploiting the other source.
In 2501 a terran probe detected the terrazine. The Terran Dominion established Project Shadowblade here under the command of General Horace Warfield in order to test the psi-enhancing properties of terrazine.
The project eventually expanded to include psychic terrans. One project member, Cole Bennett, was a strong psychic and had infiltrated the project in order to test the product on himself and others. When this was discovered, General Warfield shut down the project, and it was terminated. Bennett escaped and plotted revenge in his other secret identity, Jackson Hauler.