Stand Virus

This unidentified virus originated from an unidentified asteroid that struck Greenland 50,000 years ago, and can awaken Stands, psychic manifestations of life energy, within Humans and other living beings.

Biology
This virus takes the form of reddish-pink bumpy spheres, presumably far smaller than the average cell, like other viruses, and is capable of surviving in both the vacuum of space and Earth's atmosphere, as well as surviving an asteroid impact. The virus is capable of infecting Humans, cats, rats, and presumably all other living beings, even non-living beings, such as vampires. Upon infection, patients fall ill as blisters soon appear all over their bodies, quickly swelling up into bleeding tumor-like growths, causing their bodies to deteriorate, killing them after 48 hours. The virus is spread on contact, and clings to non-living substances, such as the metal of the asteroid it was found in. The virus is also able to remain inert for thousands of years until entering a host.

While there is no cure for the virus, the most notable trait of the virus is that if an infected lifeform manages to survive the initial stages of infection, the virus will stop attacking their bodies, and instead grant the host a Stand, a manifestation of the host's life energy, which could manifest as a humanoid, an effect, or practically anything else. The only hosts who survive are those who have a strong soul and willpower, as if deemed worthy by the virus, and the Stands of those who survive are granted after a flash of light. Also notably, even victims who are not worthy are known to gain Stands even while dying.

The virus is possibly sapient, as when a meteorite chunk was fashioned into arrows, the arrows would redirect their own trajectories towards those deemed worthy of gaining a Stand. Virus-coated arrows are also known to strike a person who already has a Stand multiple times, enhancing their Stands, and on incredibly rare occasions with unknown parameters, the virus somehow infects Stands, granting them incredible and unpredictable power referred to as Requiem.

History
50,000 years ago, an asteroid carrying this virus landed on Earth, in what would later be known as Cape York, Greenland, possibly by chance or from the virus itself redirecting the asteroid. Centuries prior to 1978, a Human man discovered the meteor and learned of the virus, presumably getting a Stand himself from it. He then took chunks off of the meteor and fashioned it into a group of ornate arrows, seeking god-like power. The arrows passed around the world throughout history, and in 1978, an excavation team investigated the meteor. Two of the men touched the meteor, and were infected by the virus. Due to being too weak to survive holding Stands, their bodies began to deteriorate, but one developed a Stand in his final moments, which manifested as bolts of electricity fired from his hand, randomly discharging and searing some fingers off of the doctor treating him.

The arrows were somehow lost to time in Egypt, until 1986, when an excavation team including a young Italian man suffering from a split personality, known as Diavolo, found six arrows in the desert. Taking them for himself, he later sold five of them to an elderly woman named Enya the Hag, who gave the arrows to a vampire known as Dio, using it to awaken Stands in him and his other subordinates. Diavolo used his arrow to gain a Stand, King Crimson, as the arrows eventually found their way to other people, such as the Nijimura and Kira households of Japan and Jean Pierre Polnareff of France. On certain occasions, the virus coating the arrows exhibited their apparent intelligence. One instance is when used by Yoshihiro Kira to find potential Stand users, although they seemed unable to affect the possibly alien Mikitaka Hazekura, and after giving Yoshihiro's son Yoshikage a Stand, Killer Queen, the arrow later stabbed him again, granting Killer Queen a time-looping ability, while another notable instance was an arrow redirecting itself to give Gold Experience, Stand of gang member Giorno Giovanna, status of Requiem. Some arrows were lost one way or another over the years, with at least one being destroyed, but the virus is presumably still present on Earth.