The Otomis (exonym of Nahuatl origin) are an ethno-linguistic group from central Mexico, whose antiquity is generally recognized. Having never possessed a writing system and having left no archaeological sites, the Otomi have aroused little interest from specialists in Mesoamerica.
Therefore little information. However, I will try to tell you a little more.
In the Precombian era two large groups existed.
The first is on the edge of Tlaxcaltec territory.
The second is on the edge of Huaxtec (Teenek) territory.
For the Tlaxcaltecs, the Otomies are brutes without culture, idiots.
For the Mexica, they embody bravery and ferocity. Moreover, they gave the name Otomie to an elite military order.
The group close to the Teenecks was attacked by the Mexica and subjected to taxation.
To avoid being in danger from the Mexicas, many migrated to the Tarascans.
They accepted willingly because the Otomies would henceforth form a natural defense against the Mexicas. In addition, this allowed the Tarascan to be warned of an attack by the Mexica and to prepare accordingly.
For the Tlaxcaltec they employed them as mercenaries.
Moreover, the first "Aztec" army which fought the Spanish of Cortes was an Otomies army sent by the Tlaxcalans.
do not yet have any information on the Otomies allied with the Tlaxcaltec.
So I'm going to tell you about the Otomies allied to the Teenek.
The Otomies are distinguished by their haircut.
They shaved the forehead and sides, but on the backs of their heads they left much long hair.
Their practice painting the face (red, black) or tatooed on the skin in green (turquoise green).
I have not found any traces of cotton or feather costumes from this period.
The elites wore animal skins and cotton armor (like the Aztecs)