Eldritch Pit

Eldritch pits are a geographical feature of Lyth Dar. It is unclear if they are natural or constructed but their very nature baffles the mind. Essentially they are enormous holes that go straight down forever. These pits seem to follow a lot of their own rules of nature. For example gravity pulls you towards the walls, not straight down, allowing you to walk into the pit. Vision and light ranges are both halved.

In every pit discovered thus far, there is a dark purple miasma that is ever present. It is toxic to anyone that breathes it in. While it does not kill immediately most can not last more than a few minutes. There is currently no way to guard against it, other than to not breath. For those that do not need to breath, mostly the forged, it is impossible to get any gainful rest. Something about the pit keeps anyone inside too anxious to gain any benefit.

The pits seem to be the primary source of monsters in the world. Periodically monsters just crawl out into the world. They seen entirely unaffected by the strangeness of the pits.

The pits also appear to be effected by the phases of the moons. During full moon/s the miasma is considerably thicker and monsters pour out of the pit at a much higher rate. During new moon/s the miasma is almost gone and you rarely ever see a monster emerge during a new moon. When both moons are full monsters pour out of the pits at an alarming rate. So much so that the week leading up such events are usually spent preparing fortifications. During those nights city gates are locked and not opened for anyone. 

The only other event known to effect the pit is a double solar eclipse. This has only occurred once since the arrival. The miasma changes to a deep crimson and burns everything on contact except for monsters. The pits themselves spew monsters in what can only be described as a stampede. The influx of monsters was so great it caused the Grel to end their war against the world in favor of monster hunting.