I did get one picture of the whole costume texted to me though so I will proceed.
After sanding it all down really well I gave it some slight detail.
I didn't overdo it or anything. As I've said before the reference material I had wasn't terribly detailed and in the anime the weapon itself often changes shape, so I didn't waste too much time trying to get every little bit just so. I used sand paper and just sanded the foam down until I had that little ridge down the front (you know, the one you can barely see).
I spray painted it with a red acrylic and then brushed some watered down black acrylic paint into the groove along the ridge to accentuate the detail. Lightly spraying the paint worked out alright but there were a couple spots where I sprayed it a little thicker and it actually sort of ate into the foam. I could have avoided that by either A. being more patient and spraying on thinner coats, B. painting an acrylic primer on with a brush, or C. using paper mache or Gesso (or anything like that really) to cover the foam entirely and give it a nice smooth finish before painting.
Either way, original picture for comparison:
And end result...
Sorry it's dark and whatnot. I will try to get a better picture of the sword specifically. I'm not going to even bother trying for the whole costume again. I'm kind of surprised I even got this picture.
This was such a quick project that I'm thinking about trying another one now. I was thinking either a viking sword or a big broad bladed WOW style sword. I don't know if I want to push other things back though... Decisions, decisions.
Oh well. We'll see.