The anime I am looking for is one I remember very distantly so pardon me for my lack of details. To start it off there is a school girl with brown hair down to her ears/neck who goes on a school trip. Everything starts off normal but then these monster/machine(?) things jump down and start wreaking havoc. I don’t remember what happens next but I recall that she is the reincarnation(?) of a war god and can fight the monster/machine things and is also very good at planning war tactics.
I can also faintly remember a white haired boy who I think is also a reincarnation(?) of a war god and at the end I think they kiss (they might not I don’t know.)