This article is about a subject that is from official sources but is not considered canon.
Sally is native of San Bernardino, California, along with his husband Dave Holcomb. In 2015, little more than a week before of the events of Supernatural: Cold Fire, both of them moved to Braden Heights, Indiana due to its adjacency with Evansville, Indiana, where Dave's friend, Stanley Vargus, offered him a job as night manager at a factory he owns in Evansville.
Due to her bloodline, her coming to her ancestral land (which all of Braden Heights was owned by Larkin Family in the past) she unknowingly awakened spirits of Riza Nodd and other Pontianak that dormant there by her presence.
Sally returned from her shopping trip, when unknowingly, her husband already died due to creature attack. She later his body lied down bloody in her backyard.
During the investigation of the attack, Sam, Dean, and Castiel interviewed her. Castiel using his senses, sensed nothing magical: the hexbag, runes, or any kind of magic involving here.
In second visit, they interviewed the family again looking about more of information. During their interview with Steven Vargus, which Castiel initially suspected as the culprit due to his connection to Aidan Dufford, the son of his former worker, Sally announced her pregnancy. Prompting Sam, Dean, and Castiel about the missing link of the case. She was the first person who started it.
In third visit, they asked again about the family background of Sally. Here, Marilag, revealed that Sally is the distant relative of Larkin Family, due to her great-grandaunt, Malaya Nodd, married Calvin Nodd, hence she still a distant cousin of Riza Nodd. The family connection later linked together how the Pontianak that reside here triggered by her presence. Marilag later revealed the "dark curse" that looming in Mercado family female member, as there is no happiness but only sadness and death will accompanied them during pregnancies, prompting her to leave the town for good.
In aftermath of the events, Sally decided to back to her native place, San Benardino, California, unwanted to living here, as the house was the place where her husband killed brutally and wanted the safe place to deliver her only child with Dave. Sam and and Dean paid last visit to her. Dean informed her that they finally stopped the killer. Sally asked to Sam, if the killer of his husband will brought to trial for his crime. Sam replied no trial for the killer, and lied her for good, told her it was work of murderous psychosis instead, and justice already served in another way. They unwanted to tell the truth, as the truth will be quite harsh to her, and will blamed her for all of the killings in Braden Heights. She thanked them for everything and showed them out.
Marilag later met Sam and Dean, implied that she already now about what happened here and what Sam and Dean working about. She later wondering about her option to her granddaughter to leave the town was better for her or not, and wondering about the "curse". Sam and Dean told that Sally already made good choice to put the family safety over all and the "curse" no longer exist anymore. Sam and Dean comforted her to not worry about it, they can moved out, and she will see her great-grandchild soon.