He stumbles upon the ghost of a girl named Yuuko on one of his trips around the school and eventually helps her on looking for her lost memories. It is later revealed that he is Asagi's (Asa-chan's) grandson, the child that Yuuko saves 60 years ago.
Teiichi is a 14-year-old boy with medium length light blonde hair and brown pupils. Like many of the students, he wears the uniform of Seikyou School, and wears it neatly, leaving everything buttoned in place. Teiichi is also occasionally seen wearing glasses.
As a freshman, Teiichi does not possess the cautious attitude that his seniors have when it comes to exploring the unventured areas of the school complex. He is also somewhat more courageous than expected, as he was able to calmly talk to Yuuko even upon discovering her nature as a ghost; this does not happen all the time, however, as Yuuko would find the perfect opportunity to surprise him.
Upon his involvement into the solving of the events that happened to Yuuko, he displays a certain degree of responsibility, putting himself in various situations in order to resolve the cases that he and Yuuko would handle. He also shows a mature attitude in handling paranormal cases, a trait that fits him perfectly in the school's Paranormal Investigation Club.
Meeting the Ghost of the Old School Building
Teiichi roams the Seikyou Academy campus one day, and he ends up in the school's oldest school building, lost inside the labyrinthine network of hallways left by the school's constant renovations. He soon remembers the story about a ghost that roams the building where he was, and he unexpectedly winds up at the same spot where the ghost is rumored to victimize students — a full-body mirror that is said to reel in unsuspecting people to look into it.
He is soon accompanied by a girl wearing the school's uniform and he is fortunately taken to the nearest exit by the girl. However, he gets the shock of his life when the girl introduces herself as the Ghost of the Old School Building, Yuuko Kanoe.
Throughout the days that follow, Teiichi starts to meet up with Yuuko more often, seemingly interested in her case — as a ghost who lost all memories of her death and has no lingering attachments to anyone — and it eventually culminated into Teiichi's exploration of a passageway hidden behind the mirror he stumbled upon a few days earlier. There, Teiichi sees the skeletal remains of Yuuko.
After the discovery of Yuuko's bones, the room where it was discovered would eventually become the headquarters of the Paranormal Investigation Club, a decision Teiichi and Yuuko made in order to protect her remains while they search for clues regarding her death.
Momoe and the Hidden Demon
After the founding of the Paranormal Investigation Club, Teiichi receives his first client in the name of Momoe Okonogi, a second year middle school student who becomes involved in one of the Seven Mysteries of Seikyou Academy called the "Hidden Demon". Momoe comes to plead for Teiichi's help after she fails to finish the game, fearful that she would be pursued by the demon who punishes those are unable to end the game. Teiichi decides to get himself involved in the case, and Yuuko helps out, albeit reluctantly.
Momoe receives a handmade ofuda (or charm) from Teiichi to ease her worries of the demon coming to get her; however, Teiichi did not reveal that the charm is actually a powerless fake. Meanwhile, Yuuko discusses with Teiichi the case itself, suspecting that the case is a figment of Momoe's imagination, and the only way to relieve her of the curse is to make her believe that the demon no longer exists (i.e. orchestrate a ghost purification).Later that night, Teiichi goes to take Momoe to somewhere safe while Yuuko, acting as the Hidden Demon, pursues them. Teiichi then swiftly "purifies" the Hidden Demon using a better-made ofuda (again, another powerless fake) when he gets his chance. While Momoe sees a hideous spirit sealed away by Teiichi, what exactly is going on is Teiichi sticking the ofuda on her chest.
As Yuuko hides on a nearby classroom, Teiichi checks if Momoe is alright. Momoe is unhurt during the encounter, although a bit shaken by the appearance of the ghost. After a quick show of thanks, Momoe heads back home, while Teiichi talks to Yuuko about what happened.