Sure, the plastic look-alikes of Sora's Kingdom Key look quite similar to the in-game weapon which is iconic to the KINGDOM HEARTS franchise. But never before has an authentic keyblade been forged with steel, until Tony Swatton "the master swordsmith and renowned propmaster" from the Man At Arms show decided to make one by himself, after tons of requests from fans. Take a look at the video of the forging below.
Forged using "high-speed belt grinders, scorching furnaces, and pounding power hammers", the Kingdom Key has never before looked so authentic. Although it lacks the power to vanquish heartless and lock the world's keyhole, it's still a very decent weapon, as demonstrated by Swatton himself taking the blade out to "bust up some stuff".
Source: MAN AT ARMS