From Software struggled with finding a title for Dark Souls that wasn't insulting in some way.
As the spiritual sequel to Demon's Souls, you would think Dark Souls' title came naturally to From Software. In reality, the company had to go through many different final names, with its early choices having unfortunate connotations slang-wise.
In an interview with 4Gamer (translated by Andriasang), Dark Souls director Hidetaka Miyazaki talked about some earlier revealed details from the very creepy action-RPG, in addition to revealing that the game will feature 60 hours of gameplay compared to Demon's Souls 30 to 40. During the interview, he also talked about the trouble From had with finding a name that worked.
Miyazaki said that just before From planned to unveil Dark Souls at the Tokyo Game Show in 2010, the game's name was "Dark Race." The reason behind the title was the player's role as a member of a cursed race of people. I don't think you have to know about the controversy over Resident Evil 5 to see how calling the game "Dark Race" could have been a problem.
At the end of 2010, From had two more titles in mind: "Dark Lord" and "Dark Ring." From couldn't get a trademark on "Dark Lord," so it went with "Dark Ring." In the game, a dark ring actually comes out of the player as a sign of his curse, giving the title its meaning. Unfortunately, in England "dark ring" is also slang for "anus," so From had to go back to the drawing board again.
It seems like From basically said "screw it," and went with Dark Souls. I think the final title fits the game better anyway, and lets consumers know that it's spiritually in the Demon's Souls franchise. Miyazaki's comments are a look into the challenging task of naming a product in the face of so many worldwide sensitivities.