Boneclaw

In the Dungeons & Dragons fantasy role-playing game, the boneclaw is an undead. They resemble humanoids who are half skeletal and half without skin, with their sinew and muscle exposed. The most prominent feature of the boneclaw are its claws; its three, bony fingernails seem to grow and shrink randomly between two to ten feet long, and are razor sharp. There is no single known origin of boneclaws; some say they are necromancers who have been mutated by their own experiments while others say they hail from another world.

Society
Whether to sadistically end the lives of the innocent, or due to being in the service of a necromancer or such who commands them to do so, the purpose of boneclaws is to eviscerate the living with their claws. Though they often grow and retract as they please, the Boneclaw can take full control of the length of its claws, and attacks by sneaking into the range of a foe and then lashing out with a claw growing at the speed of lightning, and skewering them through the heart. They are also tough, supposedly due to their unholiness.

Boneclaws speak Common and Abyssal. They are chaotic evil in alignment.

Campaign Settings
Boneclaws in the Forgotten Realms were created by Szass Tam to protect Thayan enclaves.

Boneclaws in Eberron were created by Droaamite necromancers working for the daughters of Sora Kell from ogre magi.

Source
Boneclaws appeared in the Monster Manual III. This was the first book in the Monster Manual range to tell where the creatures could be found in the Forgotten Realms and Eberron, hence the origins presented in the campaign settings above.