Black Sabbath appears as a large, cloaked humanoid with a robotic head bound in a Venetian hat. It materializes within any shadow near the victim, and will release an Arrow from its mouth once it grabs an opponent's soul.
It's designed after a Venetian costume, notably inspired by the work of Casanova and by the image of Death. The borders of its hat and the scarf are used to evoke the image of Medieval Italy.[1]
It has shown to have a consciousness as it "talks" to its victim, though this may be its user speaking through it.
Abilities
The Trial: Black Sabbath does not manifest unless someone disobeys its user's will, mainly by putting out a lighter and re-igniting it in Polpo's case. Once the condition is fulfilled, it materializes within the shadow near the disobedient victim and pulls out their soul (or Stand, if the said victim already has one). It then releases one of the Stand-granting Arrows from its mouth and impales the soul or the Stand. Those who have the potential will be granted with Stand abilities, while those who do not die. Polpo uses this Stand to test the recruits of the gang; it is unknown whether the Stand was born with the Arrow, or Polpo simply implanted one of Diavolo's Arrows into it. The Arrow is destroyed when Black Sabbath dies along with its user.
Shadow Control: By grabbing onto a shadow, it becomes a tangible object Black Sabbath can pull on. The ends are still attached to the victim's feet, dragging them along forcefully as the shadow is dragged into the air. It then changes shape into either themselves or (if they have one) their Stand. It is also able to freely crawl into and hide inside of a shadow even after it has materialized initially, warping from shadow to shadow. Black Sabbath, however, cannot exist outside the shadow, and will wither and vanish (but will not die) if exposed in sunlight.
Trivia
In the Meet the Gangster Beyond the Wall story arc, Polpo is seen chewing off his fingers, and in the next panel seemingly grows them back. This is never explained, but Giorno suggests that it may be part of Polpo's Stand ability.
