This is Ayre. She is a synthetic humanoid who, with a group of similar do-gooders, spent an awful long time protecting humanity from extremists of her own kind. Many of her companions, including her sister died during the struggle to keep synths from taking over Earth.
She eventually came around to the idea of unifying synthetics and humanity and joined the side of the synths fighting not for supremacy, but for equality. Things didn’t go smoothly- she ended up loosing someone extremely important to her, as well as her arm, in a human-lead raid on a camp she was staying in. She adopted the orphaned child of two of her friends assumed to have died in the raid.
Normally she has a robotic arm that fits into the shoulder mount that you can see. She traded it away for safe passage north for her and her adopted daughter.