The powerful and legendary Couatl is a large serpent with a pair of feathered wings; since it is a shape-changer, one rarely sees this form. It can speak Common, communicate freely with reptiles and avians, or may use telepathic communication with intelligent creatures. A couatl has keen senses, including paranormal, which gives it the equivalent of Darkvision with a 90-foot range. A couatl is a benevolent force of goodness, and is rarely aggressive unless first attacked.

When pressed into direct physical combat, a couatl will bite for 1d3 points of damage plus a deadly poison (save vs. Poison or die instantly). In addition, the couatl wraps about its foe, causing 2d4 points of damage from constriction each round. However, a couatl prefers to attack from the air, using spells or other powers.

A couatl casts spells as either a Magic-user (40%), Cleric (40%), or sometimes as both (20%), equivalent to its hit dice (9th level). In addition, any couatl can, at will, cast detect evil, detect invisibile, detect magic, mind reading, and read languages. A couatl can also become invisible and insubstantial (incorporeal). In this form, it moves at half speed in any direction, and can move through solid objects freely. A couatl can teleport twice per day.

A couatl can polymorph itself freely, and will not hesitate to change into another, more effective form in combat.

Couatl are a race of brightly feathered serpents with wings. They are rarely encountered and if so, would be in a remote tropical environment. They are often treated as gods by those who serve them, however couatl rarely meddle in human events.

They can polymorph themselves, turn æthereal, and cast magic. Most are equal to a 5th level mage (45%), but a few are 7th level clerics (35%). There are a handful of couatl (20%) who cast as a magic user/cleric. In combat a couatl attacks with its bite that causes 1d3 damage and the victim must save vs poison or die. A couatl can also constrict with its body. A successful attack means the beast has grabbed its victim causing 2d4 damage, with an additional 2d4 damage each round until one or the other is dead.