Abuela was a survivor of the Cordyceps brain infection outbreak, and the grandmother of Arnie. She lived with Arnie and his mother in Santa Barbara and were Hispanic. They lived near the Rattlers in hiding, evading their attempts to capture them and make them slaves at their dome.
At some point around 2039, Abuela and Arnie's mother fell sick. Fearing for their safety, and believing the Rattlers would now easily find them, Arnie ran away in the night to offer to join the Rattlers, theorizing doing so could convince the Rattlers to allow Abuela access to their medical supplies and protect them from infected attacks.