Wight

Clever, strong-willed ghasts sometimes turn on their masters - these beasts are known as wights. They seem to carry a resentment and animosity towards humans, working in disturbingly subtle ways to sow havoc. Worst yet, a ghast may lurk among its herd undetected for months, sheltered by the very community it strives to undermine. When discovered, these beasts frequently rampage, attempting to flee to the wilderness while attacking any who impede them. From there, they harry roads, slaughter game, and bellow in the night, preventing rest.

It is unknown if the surge of intellect and malignancy in wights is the development of something new, or the casting off of some ancient mental shackle.