There is a river that dips underground through a low-ceilinged cave before descending fairly gently under the grey hills to depths unknown. However, all it takes is a magic spell to lower the water level at the cave entrance to make this easily navigable by boat, as the river cave has a fairly high ceiling after the entrance… and at least one local merchant has been acquiring goods from someone along the underground river in this manner.

The very first structures along the river are attached to a small tower on the hills above and were once used by bandits but have been abandoned in recent years. The connection between the bandit dungeons and the demon’s bridge further down has been locked, barred, and sealed by the residents of the southern portion.

A few hundred feet from the river entrance is a stone bridge that spans the water with a good 12 feet of clearance between the bottom of the span and the river itself. This is “the Demon’s Bridge” and is generally occupied by a few kobold scouts working for the bitter cold demon that is their lord. This is where trades are generally made for ice-iron weapons and arrowheads – the kobolds and their liege will not harass (except verbally) those who pass below along or against the river’s flow. From the demon’s bridge there is a long hall that eventually leads to hand-smoothed natural steps leading down to further kobold lairs.

On the right side of the river (the left side of the map, as the river flows from the top of the page to the bottom) are a number of smaller dungeons, crypts and other constructions, some linked to the demon’s bridge, others fully independent. The crypts were used by an order of druids who only preserved their highest of archdruids here, awaiting the day that the natural cycle is broken and they all awaken as one to set things right again. The other structures have seen a variety of uses by merchants, bandits, kobolds and others over the years.

Heart of Darkling started as an attempt to redraw / recreate a map from a Labyrinth Lord adventure I ran in 2009. “The Great Underground” was drawn in pencil and the original disappeared in a move – and I wanted to make a version that is a little more navigable from a DM perspective.  So I simplified it, fiddled with it, and then fell in love with it.

Now the urge is to built it into a series of maps along the underground river, a sort of “Heart of Darkness” vibe set in the underdark. Since I’m already working on one multi-month megadungeon project right now, I figured I’ll aim to make this one smaller and also distinguish it by releasing all the components under the free commercial license as I draw it.

While the original map was drawn at an angle, I know that this can be a pain in the ass for those trying to use the map with a VTT, so I’ve also included a version where the grid is set to cardinal directions instead of at an angle.

This map is made available to you under a free license for personal or commercial use thanks to the awesome supporters of my Patreon Campaign. Over 400 amazingly generous people have come together to fund the site and these maps, making them free for your use.

Because of the incredible generosity of my patrons, I’m able to make these maps free for commercial use also. Each month while funding is over the $300 mark, each map that achieves the $300+ funding level will be released under this free commercial license. You can use, reuse, remix and/or modify the maps that are being published under this commercial license on a royalty-free basis as long as they include attribution (“Cartography by Dyson Logos” or “Maps by Dyson Logos”). For those that want/need a Creative Commons license, it would look something like this:

Cartography by Dyson Logos is licensed
under a Creative Commons Attribution 4.0 International License.