Pegasi, Unicorns and Centaurs are part of a single trimorphic Race. All Unicorns are male, all Pegasi are female, and Centaurs may be of either sex. Under normal circumstances, Unicorns and Pegasi interbreed, Centaurs may be included if the individual is Worthy. Pegasi usually nest in Mountains, particularly the Elfpass and Landspine Mountains, but both Races can be found throughout Worldstree.

Pegasi and Unicorns both have Equine bodies. Pegasi may be either black, white or palamino, whereas Unicorns are always white. Pegasi are, of course, winged, and Unicorns have a single central horn. Both are fully intelligent, though incapable of speech. Both Races are extraordinarily shy and show little interest in any other Race, including the Centaurs (though Unicorns do have a certain weakness for virginal Elfmaids).

Pegasi travel in Herds of ten or so, which maintain a collective Roost. Roosts are always located so that they are accesible only by air. Like Dryads, Pegasi do not raise thier male offspring, delivering them to thier Unicorn father instead. As they lay eggs and have foreknowledge of the hatchling's gender, this presents little problem - they find the father, drop the egg and return to Roost. Pegasi Herds are lead by a HerdMother, being the Eldest member. Pegasi instinctively defer to age and do not fight amongst themsleves, even though thier society is very hierachical.

Unicorns are loners. They make their homes in the most isolated Glens and Meadows, thier only company the local Little People and an occasional Faerie Dragon. Though shy, they are also very territorial and will challange any invader that might present a threat. Whereas most of the Pegasi's Magic is used in keeping it airborne, Unicorns are not so restricted and often have a variety of Knacks.