Originally, humanity and the CORE were partners who had managed to successfully colonise most of the galaxy and establish stable economies, leading humanity to a golden age; during this golden age the CORE made a breakthrough allowing the human conciousness to be transfered safely into a machine, and made this 'patterning' process mandatory as a public health measure.
Needing a way to fight back, humanity formed the ARM rebellion in an attempt to rid the galaxy of the CORE oppression.