This unique onyx shard can be worn around the neck on a chain or at the belt as a netsuke. It is smooth and curves slightly, looking almost like a miniature katana. If none of the shard's special powers are being used, the onyx radiates an aura of abjuration magic. The magic detected is the spell that locks Kura, an intelligent being from the Negative Material Plane, into the stone. Kura was tricked into the stone centuries ago by a ninja wu jen. Kura has two goals to free itself and to assist anyone who makes use of the power of darkness.
Kura has an affinity with ninja and will badger any wearer into becoming a ninja. The stone will not willingly serve non-rogues. Kura is by nature temperamental and devious. Over the Centuries that Kura has spent trapped in the shard (most of the time serving ninja) the creature has developed a strong distrust of humans.
Kura is chaotic neutral and is treated as a weapon with an Intelligence of 14, an Ego of 10, and a personality of 24. Kura speaks to its wielder by telepathy and has the following abilities, functioning as if cast by an 8th-level wu jen and usable once a day: detect invisibility, darkness 15' radius, and fly. In addition, it can generate a blade of Negative Plane energy in the shape of any medium or small melee weapon. The blade is pitch black, effectively invisible in the dark, and has a - 3 bonus to attack and damage rolls on all targets except undead. When used against undead, the item suffers a -1 penalty on attack and damage rolls.