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.