Ai

From the Metal Assault page on the Aeria Games website:
 * "Ai's childhood was a struggle against her perfect sister, Maii, to gain their parents' attention. Unlike Ai, Maii excelled at everything she tried, from gymnastics to ballet to sharpshooting. Maii later became a war hero in the R.O.C. Ai's love and jealousy grew until an incurable illness struck Maii down behind enemy lines.


 * Hoping to both surpass her sister's memory and alleviate her own guilt, Ai became determined to join the R.O.C. herself. She strives to both follow in Maii's footsteps and outperform her at every opportunity. Quick and nimble, Ai complements the team well as a forward scout."