(Capcom's primary storyline)
Neticia was originally an ordinary spider, who innocently chose a spot in an empty solitary prison cell to make her web, though the place she called home had no food for her to catch. One of the guards met Neticia while inspecting the cell, and, sensing she and him were kindred spirits, choosing to live their lives in some sheltered corner secluded from others, diligently kept feeding Neticia moths and roaches. The guard was clearly mentally unstable due to his loneliness, as he was relaxed by the sight of Neticia wrapping the bodies of her prey and sucking their fluids out. The guard went so far as, noticing how Neticia had grown, wished to make her bigger and stronger. As a result, the guard started stealing human bodies for her. The guard himself saw no harm in his actions, as the bodies themselves were dead remnants from various experiments with the t-Virus, and as such were no longer useful and left to be disposed of secretly.
The guard fed the bodies to Neticia, and the effect of the virus on Neticia was "astounding", and in no time Neticia had became as big as a man. When he ran out of bodies to feed her, the guard sent a prisoner, destined to be tortured to death by Base Commander Alfred Ashford, to Neticia's cell. This was repeated, until at last Neticia grew too big to live in a cell. The guard let Neticia crawl loose about the prison, with the ceiling becoming her new nesting place. She started randomly eating prisoners and prison officers alike, with Alfred and other soldiers not powerful enough to destroy her.
When the Organization's Special Forces Team attacked Rockfort Island in their quest to find Alexia Ashford, the guard's body became contaminated and infected with the virus, with the entire island following in another 48 hours.
With only a few hours left, the guard suddenly began hearing the noise Neticia normally makes as she crawled on the ceiling, guessing that Neticia had consumed all her food supplies and was being driven by hunger. As expected, the guard found Neticia gazing at him. The guard, not wanting to be reduced to "a souless bag of meat", silently urged Neticia to destroy all on Rockfort after his death and gave her permission to let her kill him with her fangs, consuming his corpse.
The guard's diary was found and the account of his actions and death related. Neticia herself is presumed to have been destroyed, along with most of Rockfort's facilities, when the self-destruct went off.