Formerly mages of the most skillful disposition, these beings, by seeking immortality, find that their lives can be extended only by an arcane set of magical spells and incantations known as the Lich’s Law.
The spells do grant the lich the ability to sustain his life indefinitely. However, the cost of the Lich’s Law is steep: hyper-sensitivity to light, a requirement to feed upon the flesh of the living, a gradual decay of bodily organs and skin, and a heightened sense of paranoia. It is the latter affliction which has kept liches from sharing their secrets and discoveries with each other, much to the relief of the living.
So, liches tend to lead solitary lives in isolation trying desperately to figure out how to break the limitations of the Lich’s Law. Their need of human flesh has made them pariahs to civilization and the subject of many children’s stories meant to frighten the young into obedience.