android foundries are probably the calling card of the Azlanti Star Empire (as an aside, there was a pretty cool hinted at plot point in EberronSpoiler:about the Quori and the warborn, where quori souls were being used to make the warborn and this was causing the quori to panic... no reason why that can't be made into a cool plot point for Starfinder)
There was a similar plot hook built into the TV show, Babylon 5: In the first episode, it was revealed that 11 years ago, a first contact between an Earthforce (human) exploratory starship fleet and Minbari vessels goes horribly wrong, starting the Earth-Minbari War. Earth forces were severely outmatched by the technologically superior and zealously vengeful Minbari, and within 3 years, Earth and all of humanity were facing extinction... until Minbari forces mysteriously surrendered unconditionally at the Battle of the Line. Eventually, it's revealed that...
How a Minbari soul ended up in a human pilot, and the ramifications of the Grey Council trying to keep their discovery a secret from both humans and Minbari, are major plot points explored over several seasons.