|“||Classmates should stick together, not kill each other.||”|
He has a very mysterious personality. In the anime, Kouichi Sakakibara and Reiko describe him as "The Lord of the Library." He claims that he ran away because he felt guilty, and was afraid for his life, so he became a librarian instead of a teacher to avoid the class' curse. He decided to not to leave, because running away was not the answer for him. He is always serious. In Another 0 chapters, Ryoko claimed the fact that he is not really friendly. He always dresses in black, has an emotionless expression, and not easy to get along with.
Chibiki's appearance differs greatly in the anime and manga. In the anime, he is an old man with white hair that reaches past his shoulders and black eyes. He also wears spectacles with circular lenses. In the manga, his hair is much shorter. In Another 0 chapters, in his younger days, he had dark-colored hair.
In Another 0 chapters, in 1983, when Reiko couldn't reach a book, he helped her. Later, Reiko asked for his help to stop the calamity but he said that he doesn't know a way to stop it. He is often seen in the library, and occasionally talks to Mei there.
In "Face to Face", he tells Kouichi and Mei more about the curse and how the Misaki from 26 years ago was in fact a boy. He also informs them that he is an ex-teacher who taught the 9th class in 1972, and ran away, becoming a librarian because of the fear that he would die.
In "Build Limbs" he mentions hearing of Kouichi's mother's death, and then Kouichi tells him the when and where of it. He hadn't previously known that Ritsuko was one of the class 3-3 calamity deaths.
In "Sphere Joint" he takes charge of the situation after Kubodera-sensei commits suicide. Later he remarks to Kouichi and Mei that that Kubodera-sensei had seemed unstable when both arrived at the school that morning, that he had heard from the police that Kubodera had killed his mother before coming to school. Later still that both Izumi and Ms. Mikami have consulted him about countermeasures.
In "Glass Eye", Kouichi shows Mei his mother's class photo. The purpose is to look for Misaki Yomiyama, but class 3-3's teacher at the time, Chibiki, is plainly visible in the middle of the photo. (The same was also true in "Build Limbs" when Chibiki asked Kouichi which girl in another class photo was his mother.) When Daisuke fell sick Chibiki asked everyone to call 119, but there was no signal. He then goes with Daisuke at the hospital.
In "Makeup", he is shown driving down the mountain with Daisuke in the car.
In "Stand by Oneself", he arrives back just in time to save Yuuya and Naoya from Keiko. He killed her with a knife and takes Yuuya and Naoya to his car, where he give Naoya first aid, then tells them to stay here. Not shown in the anime, he went inside the burning building, and got San, Sayuri and Yukito, who were trapped under a chandelier, out. Chibiki also stops Izumi from killing Kazami, saying that classmates shouldn't kill each other. Later, he got Kouichi and Kazami outside the building.
Days after the tragedy he encounters Kouichi and Mei at the Mikami grave. He tells them that a total of ten died due to the calamity; besides the eight students, the managers of the lodge were Ikuo's maternal grandparents and since his death they were emotionally depressed.
Main article: Tatsuji Chibiki/Image Gallery
- "You should not be doing these terrible things ... like killing your classmates."
- "There is no curse, There is no evil. Occurs naturally like a typhoon or an earthquake."
- "This is not normal."
- In the novel, he is one of the main characters, and had detailed notes of each year's death. However, unlike in the anime, he had no knowledge of Ritsuko Sakakibara's death.
- Chibiki has a wife and an unknown number of children. However, though still married they no longer live together, apparently due to Chibiki being concerned for their well being should he become 3-3's teacher again. During the events of Another his wife is in Sapporo, Hokkaido, where she was born. Chibiki visits her for an extended period of time in July.
- He is the adviser of the Drama Club, much to the shock of Kouichi and Naoya. The two couldn't believe Chibiki, who was always very severe and clad in black, was actually an actor.
- He is also shown to be a good cook. In Chapter 16, he cooked all the food for the students at the training camp.
- In the live action movie he was killed when he gets in contact with Reiko and falls down in the flames. He returned in 2012 as the "Other," now class 3-3's teacher.