Kobold

A kobold is a spirit creature that live underground. The enchanted souls of dead miners, they can be both beneficial and dangerous to miners; some use knocking to warn miners off from dangerous routes or pinpoint rich veins, while the more nefarious ones cause caveins and rock slides.

Kobolds are short, gaunt creatures, with broad heads and small, beady eyes. Their skin colour varies from black to brown, and within their chests glow faint lights. Sometimes, a kobold will turn invisible. Now unable to see, due to light not passing through its eyes, it will fly into a fit of rage, smacking anything in sight. This can cause anything from rock slides to cave ins to injuries upon miners caught in the kobold's wake.

Short story
''"I saw something!" I exclaimed. "Deep in the dark, staring daggers with... with beady eyes."''

''The foreman, following my gaze, pointed at a shape in the darkness; like a man, but shorter, gaunt-looking, with the mannerisms of a rodent, though it was hard to make out any characteristic. It did not seem to pulsate with any sort of breathing, nor move in any discernible way. It simply reared its small head to glare at us with small, white eyes.''

''"Ah," the foreman exhaled. "'Tis but a lonely kobold. A benevolent spirit, if shown respect and charity."''

''The foreman removed a slice of meat from his satchel, and tossed it into the darkness. The form seemed to flatten towards the ground, before fading into the darkness, along with the ham.''

"It will leave us be. Perhaps it will guide us further into the mine. But remember, son; if you show it courtesy, it will leave us alone. Spurn it, and prepare for it's kin to set upon you with half-material claws and wails."