This black scimitar and dagger have edges honed to a mirror finish and are connected to each other by a silver chain. You can attack while holding both weapons or, while holding only the scimitar, and swinging the dagger by the chain. While swinging the dagger in this way it is considered to have the property Reach and you attack with it as if dual wielding it with your off hand. If you attack while not holding the dagger and roll a 1 on the attack roll you are automatically hit by the dagger.
If you attack and hit with the scimitar and then on the same turn hit the same creature with the dagger the target creature takes an additional 2d8 necrotic damage. This effect does not apply if the creature is not hit by both weapons or the dagger hits before the scimitar.