The bone fairy, formally known as the osteophage, is an uncommon insect species found in various locations around the world. Adult bone fairies are unusually large, typically four to five feet tall, and appear similar to pale ashen humanoids with four arms and large wings.
This species is set apart by its unique diet, consisting mainly of teeth and bones. Due to this diet, and the vicious predatory abilities of adults, they can pose severe threats to communities of sapients if they make their nests near towns and villages.
A female osteophage can only mate and spawn once, laying a few dozen eggs, dying immediately after, and serving as the first meal of the newly hatched larvae a week or two later.
In the larval stage, sometimes known as tooth fairies, osteophages are much smaller, rarely reaching a foot in height. Tooth fairies are very attracted to small shiny objects and, as the name indicates, subsist on enamel from teeth, rather than normal bone tissue. They make poor predators and primarily survive one of two ways: either ripping teeth from the mouths of already-dead creatures, or forming a mutualistic relationship with small sapient communities. In this relationship, the humans will leave any lost teeth, especially children's baby teeth, out in view of open windows overnight, and the tooth fairies will take them and leave any shiny objects found in their place.
After spending five to ten years in the larval stage, osteophages enter a pupa constructed from dentin, and after spending a year growing within, emerge as adults, ravenous and brutal, making excellent predators with tough bone tissue hide and long claws. The adult stage lasts about five years, although it can occasionally end very early since the creatures are sexually mature from the moment they exit the pupa. They practice sexual cannibalism--after mating, the female will decapitate the male, eat its head, lay a litter of eggs, and die.
The Tooth Fairy
The strange symbiosis that larval osteophages can form with sapient communities has led to a common rural legend known as the Tooth Fairy. Many villages tell their children that if they leave their baby teeth out at night, a friendly fairy will come in to buy them. Some of these areas have actual osteophage infestations that have not yet reached the adult stage, but in most, locals have simply heard of the species or the legend, and parents swap the tooth for a copper piece or a toy.