Clamp: Referee's Notes (Extensive work to follow, but the short is as follows)
Secret History
 Clamp's 
  forest interior never fully explored, and is host to an undiscovered neolithic 
  race very, very similar to the Skiltaire. In fact, should one genetic comparisons 
  between the two races, an improbable 98% of the genes are identical, making 
  the S'ree relatives by default even if not really the same species. Theories 
  of transplantation, Ancient's manipulation, etc will likely be brought forth, 
  though there are no ancient sites anywhere within the Clamp systemt. The S'ree, 
  as they call themselves, will curious and unfearful of any outsiders that might 
  discover them. Their numbers are small (Probably less than 20,000), and they're 
  only gathered around the shores of two very heavily overgrown rivers and their 
  deltas. Their homes are usually dug into the banks of the rivers they live near 
  and feature extensive underground warrens housing extended families. There are 
  stony ruins of an older, failed civilization, covering the same region the S'ree 
  live but that belongs to another race which have vanished entirely.
Clamp's 
  forest interior never fully explored, and is host to an undiscovered neolithic 
  race very, very similar to the Skiltaire. In fact, should one genetic comparisons 
  between the two races, an improbable 98% of the genes are identical, making 
  the S'ree relatives by default even if not really the same species. Theories 
  of transplantation, Ancient's manipulation, etc will likely be brought forth, 
  though there are no ancient sites anywhere within the Clamp systemt. The S'ree, 
  as they call themselves, will curious and unfearful of any outsiders that might 
  discover them. Their numbers are small (Probably less than 20,000), and they're 
  only gathered around the shores of two very heavily overgrown rivers and their 
  deltas. Their homes are usually dug into the banks of the rivers they live near 
  and feature extensive underground warrens housing extended families. There are 
  stony ruins of an older, failed civilization, covering the same region the S'ree 
  live but that belongs to another race which have vanished entirely.
Archeological digs will take years to uncover the background of this portion of the planet's history, but eventually archeologists will be able to determine that they were originally built by a now extinct race of amphibians. Another interesting note is that the fossil record will include a whole range of extinct 'pseudo mammals', fur bearing creatures native to Clamp that have since died out entirely when the ancestors of the current amphibian life managed to outbreed out-survive them. At some point, roughly 75,000 years ago, the S'ree appeared on the planet before the last of these mammals died out, though the S'ree will also prove to be a radically different biological design from the mammals they apparently 'sprang' from. Whatever the case, the competition between the sentient amphibians the the S'ree devolved from trade to all out warfare. In a struggle lasting only a few hundred years, the S'ree not only gained the upper hand, but eliminated the competition entirely.