I made this sword by using my normal 3.0 method (check out my dagger 3.0 to see what that is), but after taping the foam to the sword, I carved it into a "sharp" edge with a jackknife. That took ages, and it was tricky, but that wasn't anything over the guard. I ended up making a guide out of a piece of cardboard (drew out the pattern and cut it out with a jackknife) and taping that to the piece of foam that was to become the guard. I then carved the guard out halfway, removed the mold, put it on the other side, and finished carving it. After that, I added stick on rhinestones. I used "tape on engravings" for a lot of it, which I make by putting a piece of electrical tape on top of a piece of foil tape and drawing on it with pencil, and in that way sort of stamping a design into it. I pencil-stamped the sea serpent on the blade the same way, though I did it while it was already on the blade and I didn't use electrical tape.
The sheath I made by wrapping two pieces of cardboard in one layer of packaging foam and then that foam in one layer of black sparkly thin craft foam.
If you want to know more about how I make weapons like this one, here's an I'ble