Bow and Arrow

The Bow and Arrow (弓と矢) (more generally the Arrow (矢)) is a powerful item introduced early in Diamond is Unbreakable.

In Part 4, it becomes a major plot-driving force for its role as the source of many new Stand users; and it is revealed that its influence extends back to Stardust Crusaders.

Some of the Arrows or fragments of Arrow-heads also bear influence on the events of Vento Aureo and Stone Ocean; where further previous influence is detailed.

History
Approximately 50,000 years ago, a meteorite crash landed on Earth around an underpopulated region of,. In 1978, a mineral excavation team uncovered an unknown virus within the rocks of the surrounding area and determined that it had been laying dormant inside the meteorite that hit Earth long ago. Despite extensive research, government doctors were unable to determine the alien virus' purpose outside the total elimination of human life. Akin to the theory of evolution, it was discovered that certain people possessed a quality that would enable them to survive when exposed to the virus, additionally granting them supernatural abilities.

Several hundred years before the discovery of the virus, a man who wished to acquire the power of gods took the rocks and fashioned them into Arrows. These Arrows had since been lost until 1986 when an Egyptian ruins investigation team that included a young Diavolo uncovered six of them from underneath the Egypt desert. The Arrows were eventually stolen by Diavolo, who sold five of them to Enya the Hag. The Arrows allowed the wielder to unlock Stand abilities in those who had the potential to awaken one, essentially acting as the aforementioned trigger. The six Arrows were eventually distributed between various people, among them were Keicho Nijimura, Yoshihiro Kira, and Jean Pierre Polnareff.

Stand-awakening property
The Arrows fashioned from the meteorite will catalyze and awaken the Stand of any living creature they pierce.

However, if the target lacks sufficient spiritual strength, they will die if the wound is fatal. On the other hand, the Arrows normally only seek out (and pierce) those who can handle the strain to begin with.

It is theorized that the meteorite sought out Earth through the will of its many strong spirits, rather than striking the planet by chance.

Other physical effects of piercing
In certain cases, such as with Ken Oyanagi and Stray Cat, with neither of them being exposed to regeneration or regenerative abilities, the wound caused by the Arrow will heal and leave a hole about the size of an average coin.

As the origin of Joestar Family Stands
The Arrow's effects are also transferable down bloodlines, generally without exception as the Arrow that pierced Jonathan Joestar's body taken over by Dio awakened Stands in the rest of the Joestar family, with certain people without the necessary spiritual strength suffering from the strain (such as Holy Kujo and Josuke Higashikata at the time). A family member without the spiritual strength to control a Stand will be slowly overwhelmed by it as if they were suffering a severe fever as it happened with Holy Kujo and Josuke.

Arrow piercing Stand users or Stands
When a Stand user is pierced by the Arrow, as in the case with Yoshikage Kira, the Stand in question gains a new power. It should be noted, however, that in the only known example of this, the Arrow has had to move by itself and pierce the Stand user willingly.

If the Arrow pierces or cuts the Stand instead of the user, the Stand completely changes form and its powers become drastically greater than usual. In the two instances where this form was achieved, Requiem was added to the end of the Stand's name. Gold Experience has been pierced twice by Arrows but only once did it evolve into a Requiem Stand; why this phenomenon happens and how it works is unexplained.

Breaking an Arrow-head; Fragments
It is possible to break an Arrow and render it ineffective. This is largely implied to be related to the insect-like carving on the flat face of an Arrow, which, if intact, will be usable.

It can even retain its effects and seek out potential Stand users in the form of an amulet that Jotaro gave to Jolyne, as long as the insect carving on its face is intact and it is able to pierce its target.

The Arrows
Six Arrows have been revealed to date. Following their theft from an archaeological site in Egypt by Diavolo in 1986, five of the six were sold to Enya the Hag. Their subsequent provenance is outlined below:
 * 1) The Arrow kept by Diavolo, presumably used to awaken his Stand, King Crimson. Later given to Polpo and placed in the mouth of his Stand Black Sabbath in order to create Stand Users for Passione. It shatters upon Polpo's death.
 * 2) The Arrow obtained by Keicho Nijimura, who sought after it upon learning of Enya through her connection to DIO and thus his father. Used by the Nijimura brothers on various residents of Morioh in their attempts to create a Stand User capable of killing their father. Later stolen by Akira Otoishi, who uses it to grant Stands to two rats. Recovered by the Speedwagon Foundation after his defeat.
 * 3) The Arrow given to Yoshihiro Kira by Enya. Used to awaken his son's Stand Killer Queen and to create Stand Users in Morioh to protect him from the Joestar Group. Later pierces Yoshikage Kira for a second time, awakening Killer Queen's third bomb, Bites the Dust, and disappears.
 * 4) The Arrow possessing a unique beetle design, recovered in Egypt and kept by Jean Pierre Polnareff. Upon accidentally pricking Silver Chariot, it creates Chariot Requiem. Used by Polnareff to pierce Silver Chariot a second time in Rome, again summoning Chariot Requiem. It pierces and merges with Gold Experience to create Gold Experience Requiem. Subsequently enters the possession of Giorno Giovanna.

The whereabouts of the remaining two Arrows sold to Enya are unknown. However, there are several instances in the series where an unidentified Arrow appears:
 * The Arrow whose shard is used by Jolyne Cujoh to awaken her Stand Stone Free. The shard was originally possessed by Jotaro Kujo, who gave it to his ex-wife prior to the events of Stone Ocean.
 * The Arrow given to Enrico Pucci by DIO, also bearing a beetle design.  Used to awaken Pucci's Stand Whitesnake and his brother's Stand Weather Report . Its subsequent whereabouts are unknown. The anime showed that only one arrow had the beetle design, meaning that it is the arrow discovered by Polnareff in Egypt.
 * The Arrow seen hanging on DIO's wall (with accompanying Bow) in the anime adaptation of Stardust Crusaders. It is presumably one of the five sold to Enya.

Steel Ball Run
A similar case happens in the alternate universe, in a desert along the trail of the Steel Ball Run.

In this case, a meteorite crashes into the desert and forms a mobile formation of land known as the "Devil's Palm" that would change location every time and was feared by the natives near the area.

As was the case with the Arrow, it was rumored that the "Devil's Palm" sought out future Stand users, and like the Arrow, imposed a heavy affliction upon them from which the person would survive and obtain a Stand.

JoJolion
In JoJolion, an unexplained phenomenon causes several people to acquire a Stand after being bitten by something, only leaving a bite mark.