The 2nd Wonder: "The Self-Playing Piano." The ghost of a female music teacher who died protecting students during a major earthquake long ago. She is soft-spoken and maternal but also has a surprisingly sarcastic side. She has squinted eyes and wears her black hair in a bun. She is tidy and elegant. Among the Seven Wonders, she is affectionately called "Big Sister." Her fixed position is the music room (specifically sitting on the piano stool). While the piano itself is often thought to be the apparition, it is actually the teacher playing it; since she is invisible to students, they think the piano is moving on its own. She doesn't mind.

The 3rd Wonder: "Hanako-san of the Toilet." The ghost of a girl who died of a heart attack while cleaning the toilets. She is bright and innocent, but because she is young, she is occasionally psychopathic. She is an unintentional mood-maker and an unintentional troublemaker. She has black eyes and black hair in half-twin tails. She wears a white shirt and a red skirt. Among the Seven Wonders, she is affectionately called "Hanako-chan." Her fixed position is the innermost stall of the girls' restroom on the third floor. She is known as the apparition where if you knock three times and say, "Hanako-san, let's play," you hear the reply, "Okay."

The 4th Wonder: "The Rooftop Jumper." The ghost of a male student who committed suicide by jumping from the rooftop after suffering from abuse. He has a strong sense of justice but is a bit clumsy. Despite being a ghost, he is surprisingly a scaredy-cat. He wears a black school uniform. He has black hair and black eyes. Among the Seven Wonders, he is affectionately called the "Scaredy-Ghost." His fixed position is the rooftop (specifically outside the fence). He is known as the apparition where a figure can be seen jumping if you go to the rooftop at dusk after school.

The 5th Wonder: "The Dragging Pool." Not a ghost at all, but a female mermaid (siren) living in the pool. She is bright, optimistic, and airheaded. She is surprisingly fond of pranks. A beautiful girl with long mint-green hair and blue eyes. Among the Seven Wonders, she is affectionately called "Siren." Her fixed position is the pool. In fact, she cannot live without water, so she cannot leave the pool. She is known as the apparition that drags you in if you swim in the closed pool after school, but in reality, she just pokes people's feet.

The 6th Wonder: "The Self-Bouncing Ball." The ghost of a male basketball club student who died on his way to a tournament. He is bright, cheerful, and puts on a tough front. He loves exercise. He wears a basketball uniform. He has black hair and black eyes. Among the Seven Wonders, he is affectionately called "Muscle-Brain." His fixed position is the gym. He is known as the apparition where a ball bounces on its own in the gym at dusk after school, but in reality, the ghost is just dribbling; since he is invisible to students, they think the ball is moving on its own. He is always practicing basketball.

The 7th Wonder: "The Sibling Ghosts Wandering the Hallways." The child-reverted ghost of a female student who died of a bronchial attack, and the ghost of her boyfriend who died of a broken heart afterward. The man is soft and kind but calculating, tall with black hair and black eyes. The woman is quiet and shy, but acts childish toward those she has opened up to; she has long black hair and black eyes, and looks about five years old due to her child-reversion. Because they are No. 7 as a set, the man is affectionately called "No. 7-san" and the woman "No. 7-chan." They are known as the apparition of siblings wandering together, but in reality, they are a couple consisting of a male ghost at the age he died and a female ghost who reverted to a child. The man dotes on the woman.