Dark Tartarus is a Doom II megawad designed for ZDoom-based ports, created by lihanchi. It is a set of very challenging maps, many veering into slaughter map territory on higher difficulties, often with novel, eclectic concepts and themes that set it apart from many other challenging WADs.
Development for Dark Tartarus began in late 2012, with the first version of the mod, containing 32 maps, released on December of that year. This was followed in January by a patch, tartarus-sns, which added minor tweaks and fixed some compatibility issues with the software renderer, and later by version 2 which included significant map overhauls. Version 3, besides having even more changes to the original 32 maps, saw the addition of a new episode called Dark Tartarus: Dead Tonight. While the lineup of original maps remained unchanged over the next two updates, Version 4 and 5, the set of maps for Dead Tonight changed between each version, with the latest, Version 5, released in April 2015, having a total of 43 maps.