Barghest

Barghests were evil fiendish shapechanger lupines.

Physical description
In its normal form, it resembled a goblin–wolf hybrid with monstrous jaws and razor sharp claws. As whelps, barghests looked like common wolves, except for their size and paws. As they grew larger and more powerful, their skin darkened to bluish-red and eventually turned completely blue. A full-grown barghest was about 6 feet (180 cm) long and weighed 180 pounds (82 kg). A barghest’s eyes glowed orange when the creature became excited.

Abilities
While they had a variety of magical powers, barghests were feared for their ability to consume those they slay and absorb their powers. Young barghests could not attain standing in their society until they had slain and consumed a number of great mortal heroes. Eventually, these monsters shed their skin and transformed into a greater barghest.

Society
Barghests originated from the plane of Gehenna but were sent to the Prime Material Plane to mature. Once they reached maturity, they were allowed to return to their native plane. Their method of doing this was gruesome in nature. To grow and become stronger, the barghest, known as a barghest whelp in its formative years, must devour victims in order to gain size and strength. The stronger the victim consumed, the more power was attributed to the whelp.

Ecology
Barghests were terrible outsiders who came to the mortal world to feed upon its heroes. These wolf-like creatures had an affinity with goblins, and could assume the form of a goblin or wolf at will. Many goblins worshiped barghests as gods.

History
A barghest named Ulgulu lived out his early years around the region of Sundabar and became very strong after many such consumptions, so strong in fact as to be near able to return to Gehenna. In 1341 DR, he slew a farmer family called the Thistledowns, and devoured the eldest daughter. In the process, he left false evidence to point the blame at the drow ranger Drizzt Do'Urden so as to cover his crimes. In revenge for the slain family, the dark elf killed Ulgulu, along with the creature's minions and brother Kempfana. Ulgulu died halfway between changing back from the form of a gigantic wolf, proving the barghest's ability to shape change.