Their unique unit is the Jaguar Warrior, the highest rank of warrior in the Aztec army, wielding a wooden club studded with obsidian sharp shards. The Jaguar Warrior is thus a heavy infantry unit which is strong against other infantry units. Their Castle Age unique technology, Atlatl, represents a tool employed by hunters and Warriors that was used for throwing spears or javelins. Their Imperial Age unique technology, Garland Wars, references the "flower wars" which the Aztecs organized among their allies in order to provide more sacrifices. The Aztecs were also known as a hard working and innovative civilization, and their Villagers carry more resources (and got the Loom technology free before The Forgotten). Being a highly military civilization, the Aztecs also have a general creation speed bonus across the board for all their military units. They were famous for their bloody and ardent faith, with their Relics generating extra gold and their Monks receiving extra HP per each Monastery technology researched, allowing their Monks to join other soldiers on the battlefield. The Aztecs did not have horses or gunpowder. Thus, they completely lack Stables (and with it the entire cavalry branch) and cannons. Also, they start random map games with an Eagle Scout (an Eagle Warrior in The Conquerors) as a scouting unit instead of a Scout Cavalry.
In-game, Aztec units are supposed to speak Classical Nahuatl, but the in-game voices are not even close to any dialect of Nahuatl. They are probably from some Mayan language, though the exact source language is unknown.
Lumberjack is pronounced like ajsi, which means lumberjack in some Mayan languages such as Yucatec (si means wood and aj- is a prefix which forms names of profession).
Fisherman (female) is pronounced somewhat like ajkix. The first part, aj-, is probably the same prefix as ajsi (lumberjack), and the second, kix, means fish in another Mayan language: Mam. Similarly, ajtsaq (builder) means bricklayer in several Mayan languages such as Kaqchikel.
So they are possibly from some Mayan language, such as Yucatec, Kaqchikel, Quiche, or Mam, but they do not exactly conform with any of these languages.
When playing a random map game against the computer, the player may encounter any of the following Aztec AI characters:
Acamapichtli (1356-1395): First ruler (tlatoani) of the city state Tenochtitlan, ruled from 1376-1395. Astute politician who favored diplomacy above war.
Ahuitzotol (?-1502): Eighth ruler of Tenochtitlan, ruled from 1486-1502. Greatly expanded Aztec territory and further developed Tenochtitlan.
Axayactl (1449-1481): Sixth ruler of Tenochtitlan, ruled from 1469-1481. Led some successful military campaigns, but was also responsible for the first major Aztec defeat at the hands of the Tarascans.
Chimalpopoca (1397-1427): Third ruler of the city state Tenochtitlan, ruled from 1417-1427. Presumably killed by Itzcoatl in a coup d'etat, while the Tepanecs were blamed.
Cuauhtemoc (1497-1525): Eleventh and last Aztec ruler (1520-1521). Taken prisoner after the Siege of Tenochtitlan, eventually tortured and hanged by Cortes.
Cuitlauac (1476-1520): Tenth ruler of Tenochtitlan, ruled in 1520 for 80 days after which he died in a smallpox epidemic. Led the Aztec rebellion against the Spanish occupation of Tenochtitlan.
Huitzilihuitl (1379-1417): Second ruler of the city state Tenochtitlan, ruled from 1396-1417. While young and inexperienced, he sought alliances with neighboring city states and made war on Texcoco.
Itzcoatl (?-1440): Fourth ruler of Tenochtitlan, ruled from 1428-1440. Threw off the domination of the Tepanecs and forged the Triple Alliance, forming the basis of the Aztec empire.
Maxixca (?-1520): Chief of the Tlascalans and ally of Cortes, helped him recover and reassemble a host after La Noche Triste and the Battle of Otumba. Died of smallpox.
Montezuma: Montezuma II (1466-1520), ninth ruler of Tenochtitlan, ruled from 1502-1520. The Aztec empire reached its greatest extent. Made prisoner during the Spanish conquest, and killed during the Aztec rebellion.
Tizoc (?-1486): Seventh ruler of Tenochtitlan, ruled from 1481-1486. Suggested to have died from illness or poison.
The Native American building sets in the Castle Age and Imperial Age are based on Aztec architecture. However, in reality, Mesoamerican buildings were covered with plaster and had colorful walls, while the in-game depiction shows them with bare stone walls similar to how the ruins of Mesoamerican buildings look like today.