It was really a difficult enterprise to find all things for this costume, but at the end we found them, and the costume resulted really cool.

Here a little tutorial, "How to make the sword"

The blade was made of 3cm thick multilayer plywood, to get the correct
shape I printed an image on the sword, measured it a replicated it on
the wood in a bigger scale.
Then it has been cut with a jigsaw, the
edge of the blade has been made thinner with a jointer plane and
finished with sandpaper.
The hilt was done with an iron pipe welded
with a flat iron band 3cm wide so that the 2 formed a T. I drilled 2
holes in the iron band to allow the passage of 2 long screws for wood
that fixed the hilt with th lower part of the blade.
All the blade has been first painted with black acrylic spray, then the edge in silver
color, using masking tape to give the correct shape. The yellow
decoration was made with a stencil and yellow spray paint, then
finished with white and black markers to give a 3D effect.

The red and green pattern on the hilt has been made with pieces of lenci glued on
the pipe and then covered with a transparent thermo retractile tube
(normally used for electric components and wires).

The best way to make it shrink is with a hot air gun, but also an hairdryer can do
with a bit more of patience. Last the golden decorations on the two
extremities of the hilt are made with a cardboard tube just larger
that the iron tube and 4 plastic rings for curtains.