World 41 is the world where Postremo Domus is located.
After the earth becomes uninhabital, a (relatively) select few of human kind pack their bags and set off to start anew elsewhere. Thus, Postremo Domus is born.
Supposedly the last outpost of humanity. Just about everything is artificial but that's OK because no one remembers any other way of life so organic living would probably kill them.
Androids were invented long before the evacuation of earth, but the technology reached it's peak after the foundation of Postremo Domus.