(In the future, please include a picture of your character, since not everyone knows what Overwatch is.)
Do you have any sewing experience? If not, this will be a bit challenging, coats can be a bit tricky and adjusting patterns isn't always easy.
I'd use this pattern as a base, (https://mccallpattern.mccall.com/m7374
) disregard the lapels, shorten the sleeves, and add a hood. There are patterns like this one for sale, (http://www.simplicity.com/simplicity...mes/S8238.html
) or you could look up how to draft your own hood pattern from scratch or by copying a hoodie you already own.
I'm not sure how to work the large shoulders into the coat though, sorry.