The Iron Black has a peculiar, cross-like shape, with its blade split into two pieces. The middle blade is long, with a wide, flat tip and concave sides. The side blade fans out and sports two circular notches in its outer edge. The counterweight is of a similar shape and size to the side blade, though a bit smaller and lacking the notches. Both blades and the counterweight are black with red edges. The three blades are connected by a thick, white cross with red edges attached to the handle. The top tip of the handle is pale yellow and the pommel is decorated by a bronze spike, while the rest of the handle is blue-grey.
"Iron black" reflects the weapon's coloration, and is one of several of Lexaeus's weapons named after a mineral.
The Iron Black's ground combo starts with a quick, one-handed thrust that resembles a guard or block-like motion, followed by a one-handed upward diagonal slash. A very quick upward slash follows this and the combo ends with a powerful, two-handed downward slam.
The aerial combo consists of a two-handed upward slash followed by a one-handed sideways slash.