Dark Souls is a critically acclaimed game, developed by From Software, known for its high level of difficulty and innovative online features. The problem? It's not on PC!
A port of this game has a high chance of being extremely successful for From Software and Namco Bandai. Given the sales of games such as The Elder Scrolls: Skyrim and The Witcher, there is a large market for games like this. PC gamers love unforgiving, hardcore games.
A port may also mean that the area's in the game, such as Blighttown, won't suffer from slowdown. An online oriented video game is also perfect for the capabilities of a PC. Steam would also be suitable venue provided the game is sold at a reasonable price for a late port. Steamworks could provide a strong and easy to use online infrastructure.