Honestly? I consider Dark Souls to be more of an action game with RPG trappings than an actual RPG. If I had to stick between the two, it's a JRPG on a technical sense of being classified for some odd reason as one and it happened to be made in Japan. Stylistically, it's closer to a WRPG in terms of design when placed on a historical background. The most "traditional" JRPG that Dark Souls comes close to feeling like, barring the the fact the series as a whole is a spiritual successor to Demon's Souls which itself is a spiritual successor to King's Field, would be Vagrant Story; and that game itself falls into the weird design issue of not fitting neatly into its genre category either.

In the end though, who really gives a damn what genre it is, it's a great game regardless.