It is said that while Pidgeot move faster than sound, Ninjask move faster than light. This is an exaggeration, at least in the latter pokemon's case; it is more accurate to say Ninjask are much faster than the optic nerve and the brain. This saying recalls another connection between these two pokemon: because Ninjask are well able to outfly any predator except Pidgeot, it is thought that the Ninjask's high speed developed as a means of evading them, although a Pidgeot who approaches from behind can sometimes take advantage of Ninjask's poor acceleration and sink their talons into one.
Yet if this theory explains the initial development of their speed, it does little to explain the exponential speed boosts which Ninjask gain in mid-flight. As many trainers have learned to their chagrin, a Ninjask which has been allowed to fly for too long becomes all but impossible to hit and will usually defeat six pokemon with ease. When other pokemon try to attack them, they appear to make contact when using special attacks, yet Ninjask continue flying without even a scratch; with physical attacks, the body part used moves through the Ninjask like it was using Double Team. Only techniques with perfect accuracy or pokemon who have studied its flight patterns can hit Ninjask's astronomical speed. The rest score a direct hit on where the Ninjask was a few seconds ago and can only lose; whenever only one pokemon can attack, that pokemon, however weak its techniques, will inevitably be the victor.
The true secret of how modern Ninjask gained their speed can be found in Fuchsia City. The method of breeding they used is known only to the Koga clan, but their motive is transparent: what ninja wouldn't want a pokemon too quick to be seen?