Black Steel Blades were katana made of Blacksteel, a low-grade Rokugani steel, dusted with corrupted obsidian during the forging process. It resulted in a dark-toned blade whose wounds were notably more painful. These weapons were considered the Sacred Weapons of the Spider Clan. After the Destroyer War, the Spider Clan was granted Great Clan status in exchange for protection from the Taint for all Rokugani unwilling to accept it. This reduced the potency of the Black Steel Blades significantly.