When is a blade not a blade? When it's a spear!

To all examinations, the desc and name imply it should be a sword, but it's a spear. A compliment to the stealth and style of the agile assassin's guild, this is said to be the gift to the most dangerous of assassins, from the Dai Taisangu, the Eldest of the guild. Black strands of leather fall freely from a hilt crafted of solid, shining black rock. The blade curves just slightly at the end, glinting wickedly its black edge. "taisangu" the blade of a master assassin is a spear, made of onyx, and weighs 8 pounds 9 ounces.