What happens between "The Rise And Fall Of ..." to get us to the Terran Empire and then Termight?
Okay - *deep breath*
Humanity goes on developing space travel (as seen in 'Rise and Fall...'), continuing their exploration and expansion to other worlds, like the industiral colonies of Mars, but Earth grows abused and overcrowded in the meantime. In time mankind begins to move downward, hollowing out the planet itself for more room, and this presumably brings about the first re-naming of the home world - Terra, rather than Earth. Terrans build huge cities beneath their planet's crust - Necropolis, Agartha and Mausoleum among them - and a vast network of travel tubes to get about.
Having settled underground, mankind looks to new symbols of worship beyond the traditional, but increasingly obsolete, worship of the sun and moon. The worm becomes a symbol of the cosmic mother, with the Black Hole venerated as a great worm-hole in time and space - the worm's soft, flexible shape encouraging a friendly, benevolent attitude to aliens. The matriarchal worm religion exists alongside the more aggressive, partiarchal termite religion, suggested by the likness of Terra's underground warrens to insect mounds - and indeed this religion views men as mere insects, obsessed with work, cogs in a machine.
The pace of
outerspace exploration obviously isn't going fast enough for one Emperor Zalinn. He orders the creation of an artificial black and white hole on Terra itself - the greatest engineering achivement of all time, a highway to the heavens that enables Terran troops to conquer and subjugate a thousand planets, until Terra is the heart of a sprawling galactic empire, built upon purloined alien wealth. Thus the 'Classical Age' of Terra begins. Belieiving their empire will last forever, they call themselves 'The Eternals.'
But this moniker has a double meaning - a byproduct of the black/white holes is the release of tachyon particles. The engineers do their best to ensure the planet isn't affected, but some leakage is unavoidable - seepage into overland renders the Terran surface a bleak, inhospitable and hostile place. Humankind's elite choose to see this time radiation as a great benefit. It enables them to extend their lifespans to a previously undreamt-of degree - 'regression' - allowing Zalinn to oversee the entirety of the two-century long black hole build, and cementing the dominance of the classical age.
Then the rot sets in.
The secrect of time radiation leads to a huge population explosion, and the dreaming spires of the Eternal cities start to become a seething, nightmare nest of humanity - never have they more resembled a termite's nest. People begin to question the wisdom of Zalinn's bequeathing such a dangerous legacy to threaten future generations. Time waste of the disposed anti-tachyon particles begins to cause other dangerous instabilities, such as they caused on the planet's surface centuuries previously. The empire starts to decay under a sucsession of weak rulers, culminating in the supremely decadent reign of Emperor Thano III, who permits alien and human intermarriage and remains oblivious to all concern or protest as the Terran empire begins to rot around him. Thano dies in the destruction of Agartha by the Monad, an event which signals not only the end of the Classic Age, but heralds the Fall of Science.
The inevitable backlash allows the Chief of the Tube Police, one Tomas de Torquemada, to seize power in a particularly bloody coup. There are few to oppose him and his force of terminators. Science and alien culture are scapegoated as the twin evils that have brought disaster to mankind. All alien life is ejected from Terra and mankind's space expansion becomes ruthlessly agressive. Books are burned, computers destroyed, the secrets of robotics are lost and thousands of scientists are butchered in anti-science riots. The alien-friendly nature of the cult of the worm makes it suspect under the new regime, and its followers are persecuted and burned as alien-lovers and heretics. In its abscence, humanity turns wholeheartedly to the termite religion. Torquemada declares himself head of the Church of Termite - unifying church and state - and renames Terra 'Termight' to ensure that the old religion could never emerge again.
Et voila. Enter Nemesis.