Budogaoka High School Spirit
It is unknown how she looked like while alive aside from being an teenage girl who presumably wore a sailor fuku. While as a ghost, Koichi described seeing her as a black shadow that looks just like a long haired girl.
Her personality while alive nor as a ghost is unknown.
She was at least passionate about her ability to play the piano. This passion led her to be confident in her skill level and determined to put in the extra time and effort to be prepared to rank highly in something like a piano competition. After an accident caused her hands to be paralyzed, she fell into despair because she would never be able to play the piano again. These feelings persisted enough that she would eventually commit suicide due to her situation.
- Main article: Ghost
She is dead, but her spirit lives on as a ghost, haunting Budogaoka High School at night. She can manipulate objects within the school, allowing her to play the piano and make phones ring. If someone picks up a phone she made ring, they'll hear the sound of rainfall coming from it, and eventually, her saying the line "Let me play the piano." The sound of wet footsteps can be heard from them when they walk around.
Instrumental Skills: She is proficient at playing the piano, enough so that she hoped to rank highly in a piano competition. She often practiced with a music teacher, enough so that it's said that her piano music could be heard throughout the school halls every day after class. However, after an accident, her hands became paralyzed, thus making her unable to play ever again.
Ten years before the events of Diamond is Unbreakable, she was an excellent piano player who attended Budogaoka High School. She had hopes to rank highly in an upcoming piano competition, so she practiced fervently with guidance from a music teacher. It's said her piano music filled the halls every day after class. On the day of the competition, she had gotten in a car crash. Although she survived the crash, her hands became paralyzed and she could never play the piano ever again. Due to this twist of fate, she fell into despair and on one rainy day, she killed herself by jumping out of the window of the music room.
A few days after her death, the music teacher that helped her was working late at night. She made them hear the sound of a piano. Recognizing it sounded like the way she played it, he went to investigate but she ended the performance with a loud crash. She then made a nearby phone start ringing, prompting the frightened teacher to answer it and from the receiver was the sound of rainfall and then she spoke "Let me play the piano."
Hazamada's cousin attended the high school at that time as well. He heard about her suicide and the rumors that her ghost would appear at school. At some later point, they told Hazamada about this.
Two days before before the events of the story, Owada was at the school at night when he started to hear a piano playing and then a phone started ringing but he was too afraid to pick it up. In reality, this incident was a prank Hazamada did with the use of Surface to scare him, replicating the actions told in stories about the spirit.
Okuyasu knew about the stories about the spirit and told Josuke and Koichi about it, including Owada's incident, unbeknownst to them that the incident with Owada was false in its connection to the spirit. Regardless, this convinced the three of them to investigate the school at night. The decision was also influenced by the notion of checking out anything that sounds suspicious due to the events of Rohan Kishibe's Adventure happening a few days prior.
After arriving at the school at night, they seemed to be experiencing signs that the spirit was real while there. However, they eventually figured out that Hazamada and Surface were the cause of it due to him taking advantage of the idea to scare them all. Josuke accused him of making everything up in the story to scare them, but Hazamada asserted that he didn't make it up and borrowed it from his cousin, who went to the school at the time of her death.
As they are all together, the group beings to hear wet footsteps approach them, with Hazamada reaffirming that this wasn't Surface's doing. The sounds suddenly stop, but then Koichi notices a black shadow with the appearance of a long haired girl standing right behind Josuke. She says, "Let me play the piano." aloud to the group. The terrified group then ran away from the school. Koichi pondered if they were an unknown Stand or a ghost haunting the school, like how Reimi haunts the Ghost Alley.