Couatl

Couatls have been part of the world’s oldest role-playing game forever—Wikipedia says since 1976’s Eldritch Wizardry.  Usually they were generic planar do-gooders, though; it’s only in the last few years that they really seem to have captured designers’ imaginations.  In 3.5’s Eberron setting, they were enemies of that setting’s rakshasa lords and allies/incarnations of the Silver Flame.  And in 4th Edition, The Plane Above: Secrets of the Astral Sea casts them as scheming, status-seeking manipulators, doing or sponsoring great deeds but for self-serving reasons—one of the more interesting monster facelifts I can think of.  Meanwhile, in Pathfinder’s world of Golarion, they’re still relatively blank slates.  In your campaign, you might cast them as kin or rivals to dragons, messengers of the gods, portal guardians, cosmic chess-players, mysterious sensei, or smug serpentine jerks.

After traveling to another continent to rouse a pair of couatls—named for the East and West Winds—from their slumber, an adventuring party returns home to their elven patrons.  The couatls greet their patrons as old friends, raising questions as to the elves’ true identities and motives.

Instead of an Astral Plane, the worlds of Mol sit nestled in an airy archipelago of floating islands linked by vast root structures, waterfalls, and stepping-stones.  Couatls guard the paths between the planes, attacking yeth hounds and guiding or warning off the rare planeswalkers.  Dragons, even chromatics, honor these couatls, and call them the First Brothers.

A couatl and an ogre mage duel via proxies.  Should their various intrigues to be plotted on a map, one would discover a vast game being played, an almost living version of draughts performed by thieves guilds and musketeers.  The spoils to go to the victor include a magical ship, a singing sword, and a small library.

—Pathfinder Bestiary 49