1) how many groups of precursor are there? As far as I am aware there where 3 one group became the powder and later the flood,one group left the Galaxy and went to the large Magellanic cloud and the 3rd choose to go dormant. The group that went to the Large Magellanic Cloud where wiped out by the ancient Forerunners,the dormant ones are still unaccounted for and we all know what happened to the flood. Is it beloved that the precursors held 100billion years of experience and knowledge etc or that the race itself is 100 billon years? 3 why is Halo so good at having interesting lore yet is typically very vague while we know more about the forerunners they are still a pretty vague race the precursors are even more so.