Prior to Gorod Krovi, the last we had time we heard mention of Sophia was in Der Reise. Then we were introduced, rather suddenly, to S.O.P.H.I.A, the Strategic Operations Planning Heuristics Intelligence Analyser.
This robotic version of Doctor Maxis' secretary is odd, expecially when you consider Richtofen's quote upon meeting her in Gorod Krovi.
"Uh... Believe it or not, S.O.P.H.I.A used to be Maxis' secretary. How she became a machine, I know not."
This is proof that Sophia wa