The Justicar (born Amaya T'Shaan, later known as Reya)
The question answers itself
Appearance: Image: Amaya T'Shaan
. Note: This image was captured during Amaya's days as an Asari Commando. Since then, no one has been able to prove they've seen her face, much less snap a photo of it, as she always wears a helmet, which shows only her eyes.
Because of her strict adherence to the Justicar Code, many would call her harsh. However, few would dispute that her actions were just.
One Cerberus Skunkworks Harpy X pistol. Beyond that, she is
In developing her biotic abilities, she focused on Slam, Shockwave, and Reave. These three are her strong suits, but she is also capable of Barrier, Pull, Singularity, Throw, and Warp, though to a lesser degree.
In her early years, Amaya T'Shaan traveled incessantly. She visited as many new worlds as she could afford to. She worked aboard cargo freighters to visit worlds she couldn't afford, and learned as much as she possibly could about the people and creatures that lived there. When she was 171 years old, she returned to Thessia and settled there briefly before relocating to Illium with a Turian partner. They lived there together for twenty years and had a daughter.
At the end of that time, the Turian and their daughter disappeared without a trace. Two weeks later, an Asari Commando unit found what was left of them. Dismayed, Amaya almost reverted to her wandering life. Instead, she entered training to become a Commando herself.
During the next three-hundred years, Amaya worked hard, leaving almost no time for relaxation. Occasionally, she burned out and a concerned co-worker would take her away for a week off. But in spite of their best efforts, she always found trouble that needed their attention. She occasionally melded with people who captured her interest, and from these melds, she had two daughters. Amaya's daughters, due to the risks inherent in her profession, were raised predominantly by their fathers.
When Amaya was 518 years old, she received word that one of her daughters and both of her mates had been killed in similar manners to her first losses. In a panic, she raced to find her only living daughter. She found her daughter still living and sent her into hiding. Then, she entered training to become a Justicar.
Justicar training was no cake walk; Amaya was nearly killed three times before it was over. But when she completed it successfully, she cast off her old identity and renamed herself Reya. Though there was an assignment lined up for her if she wanted it, she declined, saying simply she already had one. Then, she hunted down and killed the group responsible for the deaths of her loved ones. Recognizing this as a violation of the Code, she spent fifty years in isolation, self-inflicted exile.
When she returned, she renewed her pledge to uphold the Justicar Code and took to wearing a helmet to conceal her identity from those who knew her. To further distance herself from the woman she had been, she gave up the name "Reya" as well, calling herself simply, "The Justicar".
For the next hundred years, she served as a Justicar, her stubborn refusal to reveal her identity making her something of a legend to those she aided. It also attracted the notice of the Citadel Council and they expressed an interest in making her a Spectre. Unfortunately, she is notoriously difficult to track down, as she almost never stays in one place for long.