Sikong Shou, Joined the army at the age of 15, currently an Imperial Guard. Often boasts about her alcohol tolerance but is actually quite average in that regard.
Weapon request on the gun. The Pixiv tags say MDR, but I don't know enough about guns to say if the above is the Desert Tech MDR or not.
It's allegedly the first version of (or even a prototype, I don't really remember) the MDR which from what I've heard was garbage when it was first released. The commercial one we see today is a vastly improved model.