Manuela was born around 1986 to master criminal Javier Hidalgo and his wife Hilda Hidalgo in the area surrounding the isolated South American village of Mixcóatl. While her father and the Sacred Snakes controlled the very lives of the local villagers, Manuela and her mother were kept in his mansion far away in safety, and were left unaware of his dealings.
When Manuela was only five years old in 1991, her mother contracted an incurable disease and was administered the t-Virus by Javier in an attempt to save her. While Hilda remained alive, the virus completely transformed her into a monster. Javier sheltered his mutated wife in a private residence and Manuela was told that she had died.
In 2001, Manuela was diagnosed with the same illness that affected her mother ten years earlier, causing her health to rapidly deteriorate. Not prepared to lose his only daughter, Javier and his men began dealing with Umbrella, a drugs company secretly designing Bio-organic weapons and selling them on the black market to bioterrorists. Samples of the t-Veronica virus were purchased at a high price. Using the regenerative abilities of Progenitor virus strains, Javier realized that he could save his daughter.
The virus also had a major flaw - it could take over the host's body and mutate horrifically. Taking this into account, Javier's gang began kidnapping local girls of a similar age to his daughter. Their vital organs were harvested and transplanted into Manuela to stop the virus from taking over.
Manuela survived the treatment and took regular transplants until 2002, when she asked the doctors how they cured her illness. Confronted by the news that many women were killed so that she may live, along with the knowledge of the mutagen's existence within her very body, Manuela ran away. Emotional over her running away, Javier released the water from his hydro-electric dam, flooding Mixcóatl. Along with this, the t-Virus was released, infecting the population.
"I don't want to live if it means others have to die."
Around this time, the American agent Leon S. Kennedy and his Special forces accomplice Jack Krauser entered the village, on a mission to arrest Javier for his dealings in the black market. The two found Manuela in a church singing to her mother, though she was unaware of who it was at the time. Her mother was stopped from killing her by Manuela's singing, which allowed Hilda's mind to gain control briefly. After fighting off Hilda, the two sought aid from Manuela in finding Javier. Although unaware of her connection to the criminal, the villagers knew a lot of him. Their guide killed before their arrival, the two employed Manuela as their unofficial replacement.
Reaching the interior of the dam, Manuela was separated from Leon and Krauser when Javier managed to get her back. The two Americans were swept away into the inner-workings of the dam by the rapids. They would find Manuela while attempting to get through a flood door after she escaped from her father. By this time, they realized that she was Javier's daughter. Leon began to suspect that she had been infected with the T-Veronica virus, though Manuela would resist answering until after they reached the road above the dam.
Reaching the mansion, Manuela discovered the corpses of the doctors who treated her, and came to the conclusion that Javier had them shot after her first escape. Further into the mansion's underground, they discovered the corpse of one of the missing girls. Leon realized that it was the organ transplants from them that kept Manuela from degenerating. Javier again tried to take back Manuela, but was interrupted by Hilda, who began to attack the two Americans. Cornering and close to killing them, she was stopped by Manuela, who began singing to her again. Weak from the lack of transplants, she was unable to sing any more and Hilda's mind was defeated by her aggressive, animalistic persona. Manuela was saved again by the two agents, who stopped Hilda from reaching her daughter. It was only after her death that Manuela finally found out what the creature was.
Escaping the mansion and awaiting a rescue chopper, they were unexpectedly attacked by a new monster also derived from the T-Veronica virus. It was Javier, himself. Manuela realized that the only way to defeat her father was to use her blood which, due to the virus, combusted upon exposure to the Earth's Nitrogen/Oxygen atmosphere.
Burning the joints of the monster, Javier suffered too much damage for his mind to keep in control. His last request was for his death, which Leon and Krauser granted.
The helicopter arrived just in time, and Manuela was treated for her wounds before being taken into the custody of the government, no changes were observed from her and she remained the same.
Manuela wears a torn and blood stained dress with a bandage around her right arm, used to hide the signs of mutation scarring her arm. She wears a few pieces of exotic jewelry resembling snakes on her left arm and her left leg and wears no shoes. Her hair is tied into twin ponytails, each on the sides of her face, while the back is left down.