The Black Shield of Falworth is a shield currently owned by Issur of the House of Usher. He had apparently won it in an Arm Wrestling tournament in Petalumeir. It has been repainted and is no longer black.
Behind the scenes[]
It is a reference to the movie, The Black Shield of Falworth. It is the reference to the coat of arms belonging to the family of Myles Falworth (a black shield with a red gryphon).
It is possible that Falworth is a figure or a region of Gloriana, but there is no evidence of this. Instead it seems to be a rather straight foreward reference to the movie of the same name.