>>21625088This character is actually from a 'Shounen-with-Yuri-elements' anime, not a mecha anime.
She is Chris Yukine, the tritagonist of Zenki Zesshou Symphogear. Her main deal is ranged combat, as is made obvious by her choice of weapons. Once a villain serving as the big bad's lieutenant before being unceremoniously backstabbed, she's since joined the protagonist's band of merry lesbians and serves as their main source of Dakka and homing lasers.
She uses a piece of crystal chipped off the Norse mythological bow Ýdalir (translated as Ichaival in-series) and carved into jewellry to transform.