The weapons of the Monster Hunter film adaptation certainly look the part, but they were no easy task to create. Items like the Greatsword had to go through multiple iterations, with early results being way too heavy for a prop.
In an interview with Polygon, Monster Hunter prop master Kerry Van Lillienfeld reveals that the first version of the Greatsword he worked on ended up being between 66 and 88 pounds. This was simply too heavy and dangerous for star Tony Jaa to use. Lillienfeld had to go back to the drawing board to cook up something that worked, which led him to a “brittle biscuit foam” version.
This version of the Greatsword ended up being the one they used in the film, which you can see above. That said, this prop wasn't easy to wield either. While it came in much lighter than the original, it still weighed 33 pounds!