Images of the character here

Sierra is agent 03

As the older sister of Vincent, Sierra has appearances to keep up as the tougher, stronger sibling compared to her dweeb brother. A cold, unkind gaze is what some get if they are lucky, and many don't even get to see her face up close as she is able to snipe them with the massive range of her eliter. Sierra is bratty, sassy, snarky and very proper sounding to differentiate herself from her sibling. While she may seem like a jerk, she does care for him and does want him to succeed... just in her own way.