Coordinates (entrance) : 2289, 2778, 0
Liches, black deaths, mummies and other un-dead sorts.
Follow the path on the map through the maze to enter the Badlands Cave "mini-hell": 2710,2890,0. There you will find one of the "rune spires", possibly the least dangerous one, at: 2875,2983,0 although there are Hell Spawns who will periodically interrupt your work.
In Mini-Hell, there is also a little known cave at: 2889,2885,0. It is absolutely devoid of life. Enter and negotiate the tunnels to:3242,2872,1 where you will find a ladder which is a one way trip to: 3240,2873,0 North West of Parian.