Tyrant of Hades — Colin Kapp

Smoothly, remorselessly, inhumanly, the controlled flow of people continued. As each of the great planetary shells approached population maximum, the surplus of mass of humanity was transported out: Mars shell, Asteroid, Jupiter. Inexorably they filled the space made ready for them by Zeus, the master-minding intelligence.
Jupiter shell, Saturn, Uranus...
But at Uranus shell the ordered, ever-outward flow stopped and the pressure of the countless billions had pushed the shell to the very edge of catastrophic breakdown.
Beyond Uranus lay ready Neptune shell. Zeus-designed, Zeus-built but no longer Zeus-controlled. Another giant intelligence had usurped all power, was refusing to operate the system that alone gave any future to Solaria.
And so it was that Maq Ancor, Master Assassin, Magician Cherry and Sine Anura became the eyes of Zeus as they journeyed to the place where all systems failed, where chaos and the Tyrant of Hades ruled.