Rock Disease

“

This curse on the Higashikata Family - your illness, I swear I'll cure it.

”

—Jobin Higashikata to his son Tsurugi, Ozon Baby's Pressure, Part 1

The Rock Disease is an affliction that particular characters suffer from, featured in the eighth part of the JoJo's Bizarre Adventure series, JoJolion.

It is a hereditary illness passed down through the Higashikata family and by extension the Joestar family.

Summary

The bodies of those who suffer from this disease are known to begin to harden like rock beginning at the age of 10. As the symptoms progress the victim loses more and more of their functions and memories until they eventually die.

The disease is a hereditary illness which always affects the firstborn of the Higashikata family. If the firstborn is a son, they will become symptomatic at age 10;^[1] daughters, however, have not had a specified age at which the disease starts to affect them. Rina Higashikata became symptomatic as an adult, in her 20s.

History

Background

Tsurugi mentions that a long time ago, the second son used to succeed the Higashikata or the family would adopt someone to serve as the next heir.^[1]

The earliest chronological example of the disease appears in the Shakedown Road arc during a flashback narrated by one of the inhabitants sitting at a bench. He recalls the rumors^[2] of Johnny Joestar travelling to America to recover the corpse of a saint in order to cure his wife of her affliction, using its ability to "remove" unwanted things and push them elsewhere.

Although he succeeds, the sickness is instead pushed onto his young son, and so in a desperate attempt, he utilizes the Spin to transfer the disease to himself before being flattened by a stone under the effects of the newly developed Les Feuilles.

JoJolion

The firstborn of every generation in the Higashikata family suffers from this disease. At some point, the family found a way to save the firstborn by having another member of the family utilize the Equivalent Exchange properties of the Mutsukabe Shrine to pass the effects of the disease to themselves.

It is Tsurugi Higashikata's fear for his inevitable development of this condition that motivates him to succumb to Yotsuyu Yagiyama's manipulation, as Yotsuyu demonstrates the ability to cure the rock disease with the use of Locacaca. However, this method remains imperfect due to the unpredictable and uncontrollable nature of the Locacaca's equivalent exchange, a problem not present in the altered Locacaca branch developed by the late Josefumi Kujo and Yoshikage Kira.

Over the course of JoJolion, Tsurugi's condition rapidly worsens as he experiences memory loss and his skin begins to melt. After Tsurugi reaches critical condition, Kaato Higashikata uses an injured Toru to perform an equivalent exchange between him and Tsurugi, using sap from the Locacaca branch to ensure the exchange benefits Tsurugi. Thus, Tsurugi is cured of the disease, which passes to a dying Toru. As Yasuho explains, this marks the end of the disease as a whole.^[3]^[4]