They published it in the US. SCEJ Studio published it in Japan. Namco-Bandai published it in EU/AUS.
For Dark Souls 1 & 2, From Software self-published in Japan and Namco-Bandai handled everywhere else.
The important bit, though, is that SCEJ Studio co-developed Demon's Souls. Sony regretted its decision not to bring Demon's Souls to the US, but thankfully ATLUS did (and they made some good dosh doing it). I imagine that for this, Sony would want to keep that sweet loot for themselves.
Also, it's totally gonna be a Shadow Tower spiritual successor, guys. I feel it in my loins.