It started out as an extensive DnD 5e homebrew, but as I worked away at it I realized that I needed to more or less start from the ground up to be able to capture the depth of Dark Souls. The biggest different I can name from DnD is the combat. Rather than relying on dice rolls, everything is determined by numbers, with players able to choose different modes of attack and methods of avoiding incoming damage. Gone are the days when your armor made you invincible to damage; if you want to stop yourself from taking damage, you need to block, dodge, or parry, just like the real thing.
There are other changes and additions as well, such as a set of "alternative lore" that I've provided. This is explained more in the doc itself but the gist is that I've made a solid, revised timeline of Dark Souls' major events so that players and DMs can have a more certain world to play in. We all love Miyazaki's vague storytelling and how much it leaves to the imagination, but IMO in a tabletop you want, at the very least, your DM to have all the answers.
With all that said, have a read and let me know what you think is good, what sucks, what's missing (there's a lot, so focus on less-obvious stuff; I know I need to write down weapons and items) and what's just weird.
Edit: Sorry if this is the completely wrong flair; overall it's a creative fan work, so that seems like the most fitting thing.