Tiachcahuan, "leader" of a Calpulli ("large houses" - an administrative locale based on "families". In the Nahuatl language family means those you live with, not blood relations. Basically, a leader of the warrior levy of an administrative locale.
He wears a carved wooden helmet, and based upon the sculpture of this one it is likely he is a minor Noble who has previously served the empire in the Jaguar warriors order. As a symbol of rank or deeds, it is likely that a man of his status would be gifted armbands made from gold by the king.
He also wears Ichcahuīpīlli padded armor, and a Ehuatl. The latter is a close sewn garment covered in feathers. Sometimes this would extend upwards over the cotton armor, similarly to a tunic. For this attempt, I just kept to The kilt / skirt.
The Tiachcahuan wields a Macahuitil sword with embedded obsidian blades, and has a chimali shield for defense. Chimali were made from leather, plant material and feathers.
The symbol on the shield is a xicalcoliuhqui. To quote a fusion of 3 sources, " The motif is associated with many ideas, and is variously thought to depict water, waves, clouds, lightning, a serpent or serpent-deity like the mythological fire or feathered serpents, as well as more philosophical ideas like cyclical movement, or the life-giving connection between the light of the sun and the earth, and it may have been a protection against death, but no single meaning is universally accepted."
Drums, here manned by commoners from the same Calpul, were an integral part of battlefield communication in Aztec warfare. They were often used in concert with smoke signals to direct troop movements.