|“||It's an invisible baby!||”|
—Josuke Higashikata about Shizuka
She wears a range of soft, light baby clothing, including a small, bobbled knit cap, and large, dark glasses (designed to hide her invisible eyes).
Shizuka is a baby of average temperament.
Her Stand activates when she is startled, frightened, or distressed, rendering her invisible. She also dislikes bright lights, as shown when she cried after Rohan used flash on his camera, inadvertently startling her.
She seems most comfortable when around Joseph Joestar.
- Main article: Achtung Baby
Shizuka's Stand, Achtung Baby, renders her invisible; as well as everything inside a certain sphere around her, when particularly distressed.
Diamond is Unbreakable
Upon discovering her, Joseph Joestar and Josuke Higashikata are thrown into a wild chase to find her, during which Joseph proves his worthiness to Josuke by slitting his wrist so that his blood would be able to track her location. From then on, Josuke saw his father as more than just any "old man" and instead recognized him as someone willing to place himself in danger for the sake of protecting an innocent life.
She briefly appeared during the Cinderella arc being held by Joseph as he and Josuke are walking and encounter Yukako. When Joseph and Josuke go to the Kameyu department store with Koichi, Rohan, Yukako, and Koichi's mother and sister, she is startled when Rohan takes pictures with flash, forcing Josuke and Joseph to rush outside as the stress caused her to turn herself and her surroundings invisible. Joseph accidentally pushes Koichi into Yukako while trying to calm Shizuka and get out of the store.
Shizuka helped Rohan Kishibe when he was attacked by Ken Oyanagi. To win the last rock-paper-scissors match, Rohan used his Heaven's Door on Shizuka to make her force Ken's hand to use rock, allowing him to win the match no matter what Ken decided to choose. She was held hostage by Ken, but Rohan convinced him to let her go in exchange for another rock-paper-scissors match.
For the rest of the series, Shizuka remains mostly carried by Joseph, who had adopted her into his family despite risking the wrath of his wife Suzi Q suspecting her to be another illegitimate child of his. Her real parents were never found.
- Shizuka's name can also be read as (じょう Jō), which when paired with her adoptive surname would make her name Jō Jōsutā.