Currently unobtainable except by purchasing from other players.
Uses:
A fast off-hand weapon, needs level 25 attack to be wielded.
Notes:
When EoC was implemented, all claws were split into their main and off-hand versions. People that already owned Black claws would have both pieces, while the off-hand black claw is currently unobtainable in any other method. These were made available to free-to-play as of 21 August 2017.