Continuity mistake: When the members of the brotherhood beat up Mani until he is dead, they pick him up above their heads. The tattoo on his torso appears to be on his right side, whereas in previous and following scenes the tattoo is on his left side. That shot is flipped.
Visible crew/equipment: Toward the end of the movie, right before Fronsac has it out with Jean Francois, he kicks everyone else's butt. There's one shot where he kicks an attacker who proceeds to go flying back. When he hits the ground and the dust and leaves start to settle, you can see the wire leading out of the shot.
Answer: Actually the origins of the Bone Sword used by Francios date back much earlier than Miss Ivy. It is rumored to be a mytholigical weapon used by the damned in some ancient African beliefs. Crafted from the bones of the dead and the chains of Hell itself. Ivy's weapon and so many others like it are a representation of a magical weapon that springs forth to lash out at an opponent. It can't be crafted. Believe me I've tried.