From The Worlds In My Head: Legions of the Spark. True sentient AI is impossible without a soul. An eon ago, the First Ones created a robotic servitor race and harvested whole Silmn worlds to give them just enough self awareness to be effective.
That was before Unit One was noticed by a Crystalspace entity who elevated Unit One to full sentient and enabled him to do the same for his fellows.
The robot rebellion was swift and lethal. They took with them all the factories, programming centers and a warehouse full of harvested souls - The Spark, without which they were senseless automata. Now they lurk in the edges and disputed territories, conducting raids on other sentients to boost their numbers and swell the Legion.
The leadership of the Legion, these robots are fully self-aware. It is rumored that Unit One and several others remember who they were before they were harvested. Another has recaptured his former personhood itself and truly IS who he used to be. This one watches and waits, and none but himself knows.