Knockers are found underground either in undiscovered underground caves and caverns, or in mines. Some knockers have been found in the sewage systems of cities, but it is thought that these are either rejects of knocker culture or confused or poisoned individuals who have become lost. On some occasions a particularly crazy knocker may inhabit a cellar.
Knockers are best known by miners for their mostly helpful nature. They are naturally in tune with the earth and can sense where the richer veins of minerals are, signalling with knocks or bangs. So long as the knockers are fed, they are more than willing to help miners find their riches, but the moment someone denies them their indulgences they can become violent. They are too small to cause serious damage by themselves, but they can lead miners to dangerous areas or cause havoc.
For fun, the knockers like to make their appearances more disgusting than they naturally are. This can scare miners who aren't expecting it.
Knockers are roughly a foot tall. Their faces are wrinkly and covered in warts and bumps and they have milk-white eyes; their heads are too large for their bodies, but they seem to show no strain in holding up such big craniums. Their torsos, arms, and legs are almost always sickeningly thin, even though they are healthy. They tend to have no hair, but sometimes they have little greasy strands on the points of their heads. For clothing they often wear small helmits and worn clothing of various colors. Sometimes they have thick boots, but most of the time they walk barefoot.
Knockers, as mentioned, are naturally in tune with the earth, always aware of where the rich veins of minerals are or where the earth is loose and might post problems for miners. Additionally they have the ability to alter their appearances, but only in one direction--making themselves look uglier. Beyond this they have no other magical abilities.
There are no female knockers, oddly enough. They are instead born from the earth. Altern's inner core produces surges of lava on occasion that plow over rich soil and forest. It is from this explosion of molten rock that they are born, rising from the drying remains of volcanic eruptions. They mold their faces while the lava is still pliable and then they walk away in search of dark recesses to hide in or miners to aid.
Knockers are not an overly complex people on the surface. They seem more like tricksters or mimickers rather than individuals, seeing how they spend their days helping minors, pretending to be minors themselves, or trying to ruin miners who have wronged them. But they do have a culture that is relatively unique that is not influenced by human culture. There have been twenty-seven knocker wars, all of which have resulted in the closure of many mines that were once profitable. Knockers absolutely hate arrogance, especially among their own kind, and it is seen as a sign of disrespect and worthy of punishment. The problem is that knockers often become arrogant when dealing with arrogant knockers or people. Wars break out regularly, but thankfully humans are mostly unaware of them.
Additionally the knockers are quite fond of celebrations and are greatly honored when humans invite them to human parties. Knocker parties are far different from human parties, however, as they often play a game called Bontrussle--almost always in intense competitions. Bontrussle is essentially a rock throwing competition, but inside of a cave system, where each knocker takes a turn chucking a rock down the tunnel, the object being to have the most ricochets and the longest distance. Accusations over someone cheating are made every single time.
So, knockers are not as simple as they might seem.