User blog comment:PlaguedWings/Demon's Souls 2: a fun little thought/@comment-6003396-20140115103409/@comment-6003396-20140116223825

Sorry if I explained things that were already known, sometimes I am too thorough. I honestly don't know for sure whether Atlus helped with development, but it was an educated guess as I've only ever seen From and Sony attributed as developers. If Atlus had published it in Japan initially, then there might be an outside chance that they had some input, but do to the fact that they only announced a release after the game's initial success in Japan, I doubt it.

By the way, I came across this when I was doing some quick searches for more info. Far from definitive, but it's interesting.