Monsters

Allip

An allip is the spectral remains of someone driven to suicide by a madness that afflicted it in life. It craves only revenge and unrelentingly pursues those who tormented it in life and pushed it over the brink.
An allip cannot speak intelligibly.

Couatl

A couatl is about 12 feet long, with a wingspan of about 15 feet. It weighs about 1,800 pounds.
Couatls speak a variety of languages, and also have the power of Telepathy

Mind Flayer

The illithid, or mind flayer, are so insidious, diabolical, and powerful that all denizens of the dark fear them. They bend others to their will and shatter enemies' minds. A mind flayer is a strange creature, standing some six feet tall, that is humanoid only in the most general terms. Its flesh is rubbery and mauve, glistening with chill slime. The creature's head looks rather like a four-tentacled octopus, made all the more horrible by a pair of bloated, white eyes. Its mouth, a revolting thing like a lamprey's maw, constantly drips and oily slime when it is not siphoning out the brains of living prey. In addition to being highly intelligent, wholly evil, and terribly sadistic, mind flayers are utterly sefl-serving. If an encounter turns against the creature, it flees at once, caring nothing for the fate of its companions or servitors. Mind flayers speak Undercommon but prefer to communicate telepathicaly.