Bow and Arrow

The Bow and Arrow (more generally the Arrow as only it is necessary for the activation of the Stand) is a powerful item introduced in early Part IV, where it becomes a major plot-driving force due to the need to locate it and its role as a source of many new stand users. It was revealed that its influence extends back to behind the scenes of Part III: Stardust Crusaders.

Function
There are six known Arrows forged from a meteorite that crashed in Greenland, although even before then, its properties were known and utilized. The stone that the meteorite consisted of will catalyze and awaken the Stand of any living creature it cuts. However, if the one cut does not have sufficient spiritual strength, he/she/it will die from the resultant spiritual strain. On the other hand, the Arrows normally only seek out (and cut) those who can handle the strain to begin with. 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. The Arrow's effects are also transferrable down bloodlines, generally without exception as the Arrow that pierced Jonathan'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 Holly Joestar and Josuke Higashikata).

One could argue that the arrow-stone meteorite sought out Earth with its many strong spirits, rather than striking the planet by chance. When a Stand user is pierced by the Arrow, as in the case with Yoshikage Kira, the Stand doesn't change, but gains a new power; the user changes in appearance as well. But if the Arrow hits the Stand instead of the Stand User, the Stand, then known as a Requiem Stand, completely changes form and its powers become extremely strong and nearly invincible.

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.

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
After the 2011 Tohoku Earthquake, the Wall Eyes sprout up in locations corresponding to the stand users.

The Arrows
Six Arrows have been found so far. All of them were originally stolen from an excavation team by Diavolo, and all but one were then sold to Enya Geil sometime during or before early Part III. They are as follows:


 * 1) Possessed by Enya Geil. Used to awaken Dio Brando's Stand. May have been the source of the shard that Jolyne received at the beginning of part Stone Ocean.
 * 2) Possessed by the Nijimura brothers' father. Later stolen by Akira Otoishi, then was taken into Speedwagon Foundation's custody.
 * 3) Possessed by Yoshihiro Kira. Current whereabouts after powering up the Stand Killer Queen with Another One Bites the Dust are unknown. Both this Arrow and Nijimura's were given to their owners by Dio and Enya.
 * 4) Possessed by Diavolo. Given to Polpo and became part of Black Sabbath. Shattered as a result of the death of Polpo and Black Sabbath. This was the Arrow that Diavolo did not sell to Enya.
 * 5) Recovered by Polnareff after his fight with Diavolo. Later entered the possession of Giorno Giovanna.
 * 6) The location and fate of the sixth Arrow is still unknown.