These tribesmen are willing to fight for European gold, and a musket apiece.
A musket is a status symbol among the tribes, even though it is not as useful in a fight as an old-fashioned and reliable bow. It is, however, a mark of personal bravery that a warrior has taken one in battle, or been considered worthy enough to have been given one of the precious weapons. These men are the most irregular of forces, unwilling to take formal army discipline, yet willing to fight like men possessed when the need arises.
In the early days of European settlement, the Native Americans were happy to work with the various foreign powers that colonized America, even forming alliances against their neighbours and other Europeans. The tribes soon became involved in trade, fought wars because of the allegiances they forged, and were forced into new alliances as old tribal enemies took up with Europeans.
These mounted auxiliary provide cheap, fast fire support on the battlefield, able to fire from the saddle as well as deliver charges with their tomahawks. Although they are not as numerous nor as well-trained as Light Dragoons, they are available from nearly the beginning for anyone who controls territories in the Americas.