Even though you can go all out to make a detailed costume replica of Ezio’s outfit from Assassin’s Creed, you can sell it by getting the colors and look of the fabric right and wearing his hidden wrist blades. Instructables user LostRite goes through the basics of making the blades, and the hardware for the weapons only cost about $10. He used drawer sliders, a letter opener for the blades, washers, bolts, and a few other parts. I applaud his resourcefulness. Here’s his first step:
Grab one of the drawer sliders and slide it as far apart as it will go. Measure on your arm about how long you want the casing of the hidden blade to be. (mine is about 7~9 inches, i forget exactly how long).
Grip the slider firmly and saw off the extra slider (the wider part)
You should be able to slide the thinner slider part out of the wider one. Do so. We are going to throw away the thinner part, but first we need to get the other smaller piece attached to it.
Bend down the piece shown in the 3rd picture with a pliers. Carefully (and close to the ground) slide off the piece with the ball bearings. Keep this piece along with the ball bearings.
Clearly, this is the kind of costume accessory you have to be very careful with. I wouldn’t recommend using anything remotely sharp in this build if you’ll be wearing a costume in convention crowds.
Read more at Instructables.