The Bow and Arrow (弓と矢 Yumi to Ya) (more generally the Arrow (矢 Ya)) 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.
Approximately 50,000 years ago, a meteorite crash landed on Earth around an underpopulated region of Cape York, Greenland. 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, Jean Pierre Polnareff, and the Speedwagon Foundation.
The stone that the meteorite consisted of will catalyze and awaken the Stand of any living creature it cuts.
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 cut) those who can handle the strain to begin with.
It is theorised 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
Sometimes when a Stand user is pierced by the Arrow, as in the case with Yoshikage Kira, the Stand in question doesn't change, but instead gains a new power. The user themself changes in appearance as well. However it should be noted that in the only known examples of this, the Arrow has had to move by itself and pierce the Stand user willingly.
Sometimes if the Arrow hits the Stand instead of the user, the Stand, then known as a Requiem Stand, completely changes form and its powers become drastically greater than usual. 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 are unexplained.
Five of the arrows shown are simpler in design and have a hole shaped in the center of the arrowhead, whilst the 6th has a beetle shaped carving on it.
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.
- Possessed by Enya the Hag and used to awaken DIO's Stand, also causing Stands to awaken within those of Joestar blood. Knowledge of this arrow was retrieved by the Speedwagon Foundation thanks to a picture of Enya with it and a bow. This Arrow is most likely the one (with an accompanying Bow) seen on DIO's wall in the anime adaptation of Stardust Crusaders. Since Jotaro thought that there was only one arrow after hearing Angelo's story, it was not retrieved at the end of Part 3.
- Found by Keicho after learning about Enya due to her relation to DIO and thus his father. Used by the brothers to create Stands in order to discover one able to kill their father. Later stolen by Akira Otoishi who tried it on two rats, then was taken into Speedwagon Foundation's custody. Probably the source of the shard that Jotaro gave to his ex-wife when they divorced and that Jolyne receives 2 or 3 years later at the beginning of Stone Ocean, though the shard's arrow design can not be identified.
- Given to Yoshihiro Kira by Enya. He used it to awake his son's Stand and years later used to create other users to protect him. Its whereabouts after powering up the Stand Killer Queen with Bites the Dust are unknown. It might have been destroyed when Yoshihiro's picture exploded.
- The arrow that Diavolo did not sell to Enya. Given to Polpo and merged with Black Sabbath to test new members of Passione. It was shattered with the death of Polpo and Black Sabbath's destruction.
- Complete arrow recovered by Polnareff in Egypt, and used to awaken the Requiem abilities of Silver Chariot and Gold Experience. Later entered the possession of Giorno Giovanna. This is the only shown arrow retrieved by Diavolo with an insect figure on it instead of a hole, though one of the 6 arrows' design is unknown since hidden behind another.
- Possibly the arrowhead given to Enrico Pucci by DIO himself, though its whereabouts are unknown as it seemingly disappeared (or returned somehow to DIO) after Pucci was pierced. Insect design. If not the sixth Arrow, then it could likely be Polnareff's arrow before the head was placed on a complete wood piece, or be the origin of Jolyne's shard.
Chain of events as described in Part 5
People shot with the Bow & Arrow
By Enya the Hag:
By Keicho Nijimura:
- Anjuro Katagiri
- Tamami Kobayashi
- Toshikazu Hazamada
- Yukako Yamagishi
- Rohan Kishibe
- Akira Otoishi
- Koichi Hirose
By Akira Otoishi:
By Yoshihiro Kira:
- Yoshikage Kira
- Ken Oyanagi
- Mikitaka Hazekura (possibly no effect)
- Yuya Fungami
- Stray Cat
- Terunosuke Miyamoto
- Masazo Kinoto
- Coco Jumbo
By Jolyne's amulet:
By Pucci's piece:
Similar phenomena in SBR & JoJolion
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.
After the 2011 Tohoku Earthquake, the Wall Eyes sprout up in locations corresponding to the Stand users.[clarification needed]