

In shape, the blade possesses a mild, gradual widening in profile until its top-third section, whence it tapers to a sharp point and, with its flat back, curves upward, with a distal taper toward the tip. A strong sheen (greenish in the anime) is aslant the blade, visible at intervals in the anime, the temper is described as an "irregular double-clove pattern" ( 乱刃・重花丁字, midareba: jūka chōji ?). The blade has a jet-black color (as played on by the sword's name, meaning "Night"), a mirror finish, and an extremely sharp edge. Otherwise, about 1/3 down each flat of the blade, centrally from the crossguard, are langets, edged the same as the crossarms. In the anime, the stones are different: three smaller, blue ones adorning the center (plus a yet smaller one topping the middle), with in-between pairs of smaller green gems, and on the ends of the arms two unequal-sized stones, the outer and inner ones respectively blue and green (and divided by single, once again smaller gems colored purple). The groove on each side is broken in the middle where a rather large, red cabochon is inset (topped by a smaller variant of itself) on each forked terminal of the guard, again on both sides, are more such red stones, this time in trios (from the outer to the inner ones decreasing in size). Centrally along the front and back sides of the guard are rectangular grooves filled with a swirly sprig relief for detail. In particular, the guard constitutes a thick, continuous bar perfectly right-angled to the blade, flat on all sides with a rectangular cross-section, but on each end being forked recurved up and down like a cross moline. The golden crossguard is extremely long to the sides, such that on Mihawk's back, especially seen from the front, the sword resembles a crucifix.

The bandage-wrapped grip (white in the manga, light-gray in the anime) has on its top a large and round cabochon of red (blue in the anime) color to serve as the pommel, being set into a circular, golden mount. Yoru's hilt is more than suitable for two-handed use at almost half the blade's length, though its length portrayal is inconsistent. While not in use, due to lacking a scabbard, Yoru is held upside-down against Mihawk's back by two simple holding loops integrated into the man's coat. It has a total length of well over two meters, being over a head taller than Mihawk (who stands at 198 cm) when placed on his back. As seen in the opening "DREAMIN' ON", Enma's anime color scheme is a violet tsuka, as well as a violet sheath.A Western-looking sword, Yoru is a cruciform and well-ornated weapon with a curved, single-edged, black blade-resembling an oversized kriegsmesser.

In its initial depictions, in the A-ra-shi: Reborn video, its tsuka is black, and its hamon is golden. Further, a little bandaging is present on the tsuka for better grip. Three pieces of cord are present on the sword: one directly above the kashira (without hanging end), another on the saya a short bit below its mouth with two hanging, tufted ends (serving as the sageo), and yet another cord further below on the saya (again no hanging end). Like the Kitetsu swords, Enma also possesses an irregular flame-shaped hamon and black no-hi. The kashira and kojiri are matching in appearance, being large with trefoil cutouts to match the tsuba the kojiri possesses an additional accent, which seems to be a wide, knobbed ring above it. Both are embellished with simple, golden, five-petaled flower motifs on each side. The tsuka is lacquered solid lilac (rather than cloth-wrapped), as is the saya. Like the Ame no Habakiri, the tsuba is trefoil-shaped, and each lobe is holed in the middle and thickly ridged. On the cover of Volume 96, Enma is seen to be a moderately curved Shobu Zukuri-style katana with a lilac and gold color scheme. After Oden's death, Enma was inherited by his daughter, Kozuki Hiyori, who would later gift the sword to Zoro in exchange for the latter allowing Shusui, a national treasure, to remain in Wano. In Oden's hands, both blades became the only weapons known to ever (until the present day) injure Kaidou. Until 20 years ago, Enma was wielded by Kozuki Oden alongside his other sword, Ame no Habakiri. Enma is one of the 21 Great Grade swords, currently in the possession of Roronoa Zoro as one of his three blades.
