From Unofficial Handbook of the Virtue Universe
From a young age Sarah LaSilvas was obsessed with super heroics. She watched films and the news about heroes, and daydreamed that she could some day be worthy of standing beside them. She wasn't born with silver hair, silver eyes and silver skin. She once had black hair, brown eyes, and tanned vaguely olive skin.
Though she trained in martial arts as a young teen, she wasn't especially talented. She trained in gymnastics, and though she found her reflexes up to the task, she was never quite talented enough in acrobatics to feel 'super'.
At the age of thirteen, laying awake in bed, Sarah found she had the ability to create small silver 'stars' from the tips of her fingers, bright shining points of light that were able to light a room. She trained herself to learn how best to use this ability, and as she did found that it slowly was turning her skin, hair, and eventually eyes, a silvery shade of grey. Taking the name Argentia as a teen she attempted to fight crime in the small town she grew up in. It went okay, but she found it unfulfilling. It wasn't the big leagues.
Changing from a costume made from a figure skater's leotard, white combat boots, and a domino mask, Sarah made her way to Paragon City.
Journey to Paragon
Her powers seemed more than adequate to put her amongst the ranks of Paragon's fledgeling heroes. She was spending more than her fair share of trips to hospitals across the city through the mediporter network, but she was showing improvement. She'd started in the streets of Atlas taking out Hellions, until before long she was tangling with the Circle of Thorns in Steel Canyon, and the Trolls in Skyway.
Not long after she'd finally gotten the hang of things, a mediporter accident had her winding up in of all places: Praetoria!
Born again in Praetorian
Not only was Sarah immediately drafted into the powers' division, but her powers had also changed. No longer could she project her power as silver bolts of lightning. Instead she could sheath herself in it to protect herself from harm whilst also delivering punishing electrical blows with her fists. Quickly she joined the resistance, not liking the extent some of them would go to but finding that preferable to assisting the regime of tyrany employed by Emperor Cole.
Finding her new power was at the level her blasts had reached when she first came to Paragon, it took her some time to become acquainted with them. In that time she learned a lot about the new city around her, and it's people. Though she was from another dimension, another world, she felt a responsibility to them she hadn't felt even to the people of Paragon. In Paragon, there was the Freedom Phalanx. In Praetoria, the people had as much to fear from the Resistance as they did from the Loyalists.
In time she found her way back to Primal Earth.
Back in Primal Earth, Sarah decided that she needed to be more than just an average heroine. She had striven to be the best she could be to save the innocent and protect the weak while being a symbol of light in the world, hope in dire situations.
After being in Praetoria, Argent Girl understood what could happen if she wasn't able to become the best heroine that she could be. Instead of being worried, or depressed, Sarah became driven.
Working harder than ever before, Sarah began to train, and patrol, as much as she could manage.
When Praetoria invaded with its warwalkers, Sarah was in the front lines. She fought face to face with the Praetors themselves, and was able to help protect Primal earth . . . but not remove the threat.
Disappearance and Reemergence
Records for Argent Girl become hazy after she briefly joined the Young Gods of the Golden Age. Dissappearing without a trace, she resurfaced some time later in a new costume, again rejoining the Young Gods soon after. Where she was, and why she was gone are a mystery. There appear to be no traces of Praetorian influences, and she has infact helped in both the effort to liberate Praetoria and the threat of Mot in Dark Astoria.