Unicorn

Once thought to be extinct the unicorn has been rediscovered far to the north. Every part of their body is incredibly useful for magic and healing but most of that knowledge has erased, far too dangerous for the god of Law to let fester in the world. Too tempting is all that power. It is easier to list the diseases and curses a dead unicorn is unable to cure. Desperate men will commit terrible acts for even a single more day on earth, especially if they fear what will happen to them in the afterlife.
The ideal form of horse, pure white with a blazing reed head. A spiral horn sprouts from the middle of their forehead with similar colorings, a base of pure white and an upper have that is sharp and colored a vivid crimson.
They were originally hunted to extinction not by the forces of Chaos but by your run of the mill poachers. No grand battles were fought to eradicate this emblem of good in the world, just simple overhunting.
It is unclear what brought them back. Were they truly even extinct or just so low in numbers as to unseen for hundreds of years. Paladins here and there are always talking about some miracle or sign of the gods that should be forthcoming. Of course they've been babbling on about this for what? 10,000 years? I suppose they're due to get it right some time. Good for them.
Highly intelligent creatures they make a perfect traveling companion if you can befriend one. They speed is too great, no mortal can hope to catch them so careful diplomacy must be deployed.
Most settlements have been abandoned in the north. Since the destruction of Tsar there is no more northern trade, it can get quite lonely even if you're traveling with a group. Fresh faces are appreciated.