The Free Companies of Khatovar were mysterious groups of armed cultists who left their world Khatovar, crossed the Plain of Glittering Stone, and entered into the homeworld via the shadowgate about 400 years before Croaker's Annals. Their goal was to bring about the Year of the Skulls, to free their imprisoned goddess, Kina.
There were ostensibly eight Companies in total, each using a magic lance as their shadowgate key. Their entry into the homeworld was recorded by the librarians of Kiaulune, who also recorded the return of all but one, back through the shadowgate, onto the Plain of Glittering Stone, and presumably to Khatovar. The Black Company, the last of the Free Companies, had lost its original mission over the centuries. They forgot Kina and that their Lance of Passion was actually a shadowgate key, and became simply a band of mercenaries that migrated slowly northward for generations. This Company would fight to prevent the Year of the Skulls, and would become Kina's most dangerous adversary.
Only the Black Company was identified by name in the Annals. All the others, which returned to Khatovar, were either wiped out by the hostile Voroshk family of sorcerers which created an empire in that world, or, were at least fully subjugated by them.