The Rakushan Firesteed is a supernatural horse that sometimes visits the hidden valleys and oases of Khalistan, Zhirgestan and the Tagrus Mountains on moonlit nights. The fabled warhorses of the deevs, the coal-black, copper-eyed Firesteeds are allowed to run free until needed by their masters. They can gallop on the winds, feet never touching the ground, and when angered their gaze when held is enough to cause things to burst into flame. (A mere glance is not enough; if a Firesteed wants to burn something, it must stare at it for several seconds uninterrupted).
No living man can ride a Rakushan Firesteed – they will run away or attack if a human comes too close and moreover being bridled is fatal to them. Firesteed stallions however may be induced to mate with mortal mares, and the Rakushan hybrids thus produced are the most precious of all horses. Prolonged contact between a Firesteed and a mortal horse will also turn the mortal horse into a Firesteed, so to get a hybrid the Firesteed must be driven away from its mate before the transformation can be completed.
The bedouin of Khalistan sometimes bring their mares to the isolated valleys and leave them overnight, and if a Firesteed mates with the mare they rush out and try to drive it away before it can transform the mare. A few dozen bedouin die every year attempting this feat …
The Firesteed’s “cannot be ridden by a man” Hook is purposely worded with a loophole. If you wish, you can make it part of your story that a Firesteed can be befriended by a female or a child character, perhaps for just one special ride to some distant land, for some epic need.