The boomerang was always my favorite weapon for Ryu! In the game it would hit every enemy. So while it didn't have the single power of a sword, hitting more than 1 monster would make so much more bang for the buck. They were also lighter, making him act faster.
ANYWAYS, I modified a Cold Steel Boomerang for this (look up their video on youtube, it's pretty impressive!). The runes were etched in with a heat knife. The whole thing was painted and coated with several coats of polyurethane.