Complex sentence: A war between the Conflux and the Humans brought the Humans almost to the brink of extinction although the humans fought them back the eventual outcome is matter for speculation as at the height of the struggle the Shift pulled the human race away.
Split into simpler sentences: A war between the Conflux and the Humans brought the Humans almost to the brink of extinction. Although the humans fought them off the eventual outcome of the war is matter for speculation as at the height of the struggle the Shift pulled the human race away.