The Detached and the Incorporated were actually two off-shoots of the same race. The Technics were a bio-mechanical species that used fabricated implants to augment many physical and psychological functions. A few hundred years ago, their technology had grown to the point that they could physically manage consciousness. This is where the divide occurred.
One faction wanted to use the tech to separate their minds from their bodies. They believed the ability to remove emotions and to throw off the confines of morality was essential to their species’ evolution.
Conversely, the other faction believed that merging consciousnesses into a collective whole would allow their species to function more effectively — a single entity rather than many disparate ones.
The truth of the matter was that both factions were, after a fashion, correct. The Detached became ruthless and aggressive while The Incorporated became altruistic and peaceful.
And both races dominated the top of the technological ladder.