"The name "Guachichile" that the Mexicans gave to these Indians meant "heads painted of red," a reference to the red dye that they used to pain their bodies, faces and hair. According to John R. Swanton, the author of "The Indian Tribes of North America," (Bureau of American Ethnology Bulletin 145-1953) classified the Guachichile tribes as part of the Uto-Aztecan linguistic family. This would make them linguistic cousins to the Aztecs.
They were a subgroup of the Chichimecs. Sort of comparable to “Ostrogoths” as a subgroup of the “Germans”.
The whole period is a bit like the ethnic stirring of the Migration Period. Of these various displaced groups, some became the Aztecs. Hard to get a fix because of the lack of contemporary written records.
One of the mummies at Gallina had red applied to her hair.