It's an interesting plot and story, and I'm not usually one to make criticism for reviews, but the grammar and run on sentences were too much for me to read on without confusion. I can't tell if its second or third person, and I can't tell if it's past, present or future.
As a tip, I suggest doing a bit of spacing so it's more understandable, and we know who's talking.
And usually, there really isn't a need to explain the characters appearances, since this is fan fiction, and most people who come to read team fortress 2 already know the characters.
I'd understand if you just want to describe them a little bit, especially if its an OC made from the characters, or their outfits are different but overall it is unnecessary in my opinion.
But anyway, just some tips to help improve the story a little bit.
You can look to others stories too for suggestions on writing.

awww engie X soldier good one keep going