Aside from the corrections made elsewhere in the thread, you might want to add the prehistoric facts about the Cycle, as we can guess from Tales and GURPS. After the creation of the Trow, there was a long period of millennial wars--but instead of a Leveller popping up every thousand years, it was a new species which arose or appeared from parts unknown and came into conflict with the Trow. The Trow were successful in every war. Finally, the last of these invaders--the Callieach--destroyed themselves, many of the Trow, and opened the Great Devoid. This apparently signalled the end of the Cycle for a long period.
Once the Younger Races came into existence, the Cycle started again (we don't know exactly when, but it seems to have been almost as soon as humanity existed), and from then on it followed the standard Leveller pattern.
--SiliconDream