Imperial City

The Arruruerie Virus is an advanced version of the Hollowfication Virus that was orginally used by Sosuke Aizen to hollowfy Shinji Hirako and the other visoreds, giving them their hollow powers. However, after Rukia Kuchiki's encounter with Aaroniero Arruruerie, Mayuri Kurotsuchi recovered his body and, after performing multiple experiments on his corpse, he managed to create a new version of this virus, named after Arruruerie himself.

This virus is very much unlike the virus used by Aizen, for starters, this virus can spread from person to person, unlike the original virus where it could only infect someone if someone else forcibly infected them. Another example would be that if the virus can infect ordinary souls instead of literally destroying them, however, if the victim is just an ordinary soul, then they will either simply die within days or in some cases, just hours, many of these souls developing an "Imcomplete Hollowfication", in which they become mindless hollow-like humanoids. They will also have what appears to be an imcomplete hollow mask, similar to an arrancar. However, if a victim possesses Reiryoku, then their incomplete hollowfication can become complete, turning them into full hollows. The only beings immune to this virus are people who already have hollow powers, such as visoreds, arrancar, etc.

However, in very rare occurences, a victim will be able to endure the virus and become a Chūkū Shinka, gaining powers similar to Arruruerie.