The Aztecas drive the Broadway, the Glendale, and the Hermes. The VLA have three different skins that will walk and drive around their territories.
As well as rivalries with all other street gangs in Los Santos. Wears turquoise." The Varrios Los Aztecas have been around since the early 80's and are one of the newer formed gangs in Los Santos. Likewise, the origins and past of their rivalry with the other Los Santos gangs - paticularly the Los Santos Vagos is also unknown, though it obviously began sometime from their origins in the early 80's, late 80's, or the early 90's.
CJ wins the competition without any violence taking place and is then introduced to Cesar Vialpando - Kendl's boyfriend. This is because the Aztecas never show-up to rob the weapons train during the mission Catalyst, where as the other three gangs were tipped off by CRASH about the train.
They are easily identifiable by their turquoise colored bandanas and 90's "cholo" style clothing.
The Aztecas have a fierce rivalry with the Los Santos Vagos, and strongly dislike the San Fierro Rifa.
CJ makes his objection to the relationship clear, and an influential (possibly an OG) Azteca member called Jose approaches CJ and confronts/insults him for his rudeness. This is odd since the Aztecas are heavily involved in arms dealing/gun running.
Fortunately, Cesar is able to influence Jose to "cool down", thus causing him to leave and possibly saving CJ's life. Either CRASH are scared of the Aztecas due to them being possibly the most heavily armed gang in Los Santos, or they avoid them because they mistakenly think they are weak due to their small size.
Remaining Aztecas are killed or in hiding while Cesar is far away from Los Santos aiding CJ and Kendl.
Throughout the rest of the middle game, the Aztecas make no appearances.
Jose is also possibly an OG/high ranking member, who is introduced during the mission "Cesar Vialpando".
The game never explains Cesar's status in the gang. It is more likely that he is a high-ranking member and not the leader due to his influence over Jose and his overall respect.
The Varrios Los Aztecas are not a major part of the story, but are first mentioned during Sweet & Kendl in which Sweet refers to Kendl's relationship with a high-ranking Azteca member - Cesar Vialpando, stating "you know we beefing".