A mysterious virus infected Sierra's home planet before her birth. It decimated her race and all other life on her planet except for the white Dragons-- which her people worshiped.
Before their demise, Sierra's people engineered a dragon DNA cocktail in an attempt to combat the killer virus. Though successful, the process took years to create and was complete too late to save their planet.
The one successful treatment of the cocktail was Sierra Starfall, who emerged from her genetic splicing womb to a world dead except for the white dragons.
Powers, Skills, and Modifications
Even before her genetic combination, Sierra came from a warrior culture and was raised as such. She was trained in the use of ranged (firearms) and close quarters combat (with a variety of weapons).
Sierra gained a number of enhanced abilities as a result of her splicing with dragon DNA, besides the intended vaccination from her's planet's deadly virus. It resulted in bestowing on her a longer and nearly ageless life, lightning fast healing, speed, agility, reflexes, and the dragon's superior vision.
Her two synthetic arms-- one cybernetic and metal, the other scaled and clawed-- are a result of a catastrophic outland mission. Rather than having a more sophisticated procedure done to heal the wounds, Sierra opted to have the two mismatched arms grafted to her instead, as a reminder of her greatest failure. She has customized them each to incorporate the iconography of her culture.