It is said that there are blades in this world which possess souls of their own, spirits forged by master smiths through the dreams of their wielders and the blood of those slain in battle. Yet even legendary swords ultimately break, as do all living things; when they do, their spirit and willpower remains whole and a Honedge rises from the corpse. Others attribute these strange ghost pokemon to warriors so attached to their weapons and their cause in war that they take the form of swords to fight on after their death.
Regardless of their origin, Honedge do not merely emulate swords in appearance; they have on many cases accompanied armies of the living into battle, causing panic in the enemy ranks, for they slashed their way through enemies without a wielder to strike back against and phased through shields and armor. They are, to be sure, significantly less powerful in this form than they will become; their life-draining tassels at the hilt are the closest they have to a genuine weapon, for Honedge must wait until evolution to come close to matching the sharpness of swords from the world of the living.
Although Honedge are often said to be bound to the world because they claim something worth fighting for, this is not true of the entire species. A few Honedge vanished after every war, but most remain tied to our world into the present day, seeking out new individual battles even after guns have made swords obsolete and war has vanished from Kalos. If anything binds the Honedge here, it is their desire to become the strongest of warriors, and their unwillingness to admit defeat to even death itself.