Speaking with GameSpot, From Software President and Dark Souls 3 Director Hidetaka Miyazaki revealed that fans who want a Demon’s Souls remake will need to talk to Sony, as they own the IP. And if a remake or remaster does happen, they probably won’t be involved:

It seems like there was a misunderstanding in a previous interview in relation to a remake or a remastering of the game, so let me reiterate here.
The Dark Souls series is Bandai Namco Entertainment’s IP, and Demon’s Souls and Bloodborne is Sony Interactive Entertainment’s IP. Hence, the decision to do a remake or remastering is under their jurisdiction.
For me and for From Software, I don’t think we’ll be involved with their happening, but it could happen through another developer.
Miyazaki offered up a similar response to comics and mobile game tie-ins for the Dark Souls series, saying that the franchise is Bandai Namco Entertainment?s IP, and collaborations have never crossed his mind before. “It’s because I figured there wouldn’t be enough time for me to work on one, and that would probably lead to something worse,” he added.
As for a potential Dark Souls movie, he said, “In regards to movies, my stance doesn’t change from what I feel about collaborations, which I mentioned earlier. It’s not my jurisdiction, nor do I think I’ll ever be involved.” However, if one does happen, he hopes it puts an emphasis on the sto...