Kotomi is a third-year student at Tomoya's school. She is the top student of the school and scores within the top 10 of the entire country. Kotomi is extremely shy and soft spoken. She has a morbid fear of strangers. Kotomi is an extremely fast reader, is well-read, and is fluent in multiple languages including English, French, and Italian. She is also fond of word games and word puns.
Despite her fear of strangers, she is very comfortable around Tomoya and is quick to warm up to him. She also insists that people refer to her as Kotomi-chan.
Kotomi was recommended to the school based on academic excellence. She is given special privilege to study on her own and her class attendance is disregarded because she is far ahead of her peers. Kotomi spends most of her time reading difficult books in the library away from fellow schoolmates. She prefers to avoid people and is socially awkward.
Kotomi's parents were both theoretical physicists. They were researching on string theory and her father, Koutarou describes the universe as a symphony of music and likens the strings to the koto (a musical instrument). Kotomi was named after the koto, and her mother, Mizue explained that "mi" translates to "beautiful". Kotomi loved her parents and name and introduces herself by explaining the meaning behind her name.
Kotomi practiced the violin when she was young. Tomoya heard her playing and approached her. Kotomi's mother invited him in to befriend Kotomi. Tomoya frequently visited her to play with her. Kotomi's father gave her a story book which she would read to Tomoya. The phrase she loves to quote is "two days ago, I saw a rabbit; yesterday, I saw a deer; today, I see Tomoya".
Kotomi's 8th Birthday
10 years prior, Kotomi's parents were said to have solved the theory of everything and they were scheduled to present their thesis in America on Kotomi's birthday. Kotomi was angry that her parents will not be able to celebrate her birthday with her and they promised to return to do so. Kotomi's father promised to buy the biggest bear plushie for her. Tomoya didn't promise to attend her birthday but she waited for him regardless.
The plane that Kotomi's parents were on crashed into the sea near the Alaskan Coast. Their colleague wanted to retrieve a copy of their thesis from Kotomi's home and revealed to Kotomi that her parents had died. She was devastated and refused to let him in. He tried to phone Kotomi but she took her mother's scissors and cut the phone line. She kept the scissors as her memento of her mother.
Kotomi locked herself in her home and ate the food that her mother had left in the refrigerator. She expected Tomoya's arrival and kept half the portion of the food for him. She realized that she was not able to acquire more food and dreaded the day the food runs out. She rationed the food by repeatedly halving the remaining portion of it. Several days later, Kotomi went to her father's study room and found a notebook. She assumed that it was the copy of the thesis paper. She blamed it for her loss and burned it.
Kotomi's home was caught on fire. Tomoya and Kotomi's parents' colleague barged in. They put the fire out and rescued the semi-conscious Kotomi. Tomoya was devastated by the event and blamed himself for causing it. Since then, Tomoya was too afraid to approach Kotomi and he eventually forgot about her.
Since then, Kotomi used her scissors to cut out mentions of her parents' name to remember them. It can be observed that her parents' are rather famous based on the number of instances of her cutting books up. Kotomi also deeply regretted burning her father's notebook and resolved to study their field of research to reproduce the thesis that she had destroyed. Kotomi still remembered Tomoya and she had also stopped playing the violin.
Kotomi was first discovered at the library when Tomoya skipped class. She sits on the floor barefoot to read and offered Tomoya lunch. Several days later, Kotomi went to invite Tomoya to the library. He took a nap as she read a book and she prepared lunch for him.
The next day, Tomoya skipped the 4th period to go to the library and Youhei followed him there. Tomoya revealed that he had been visiting Kotomi at the library and Youhei tried to talk to her. She ignored him and he was frustrated. Tomoya noticed that Kotomi was engrossed in reading and she only responds when he calls her Kotomi-chan.
Tomoya took a nap at the library again and had a dream of a fire and a girl. He invited Kotomi to befriend Nagisa and to join her drama club. Tomoya decided to introduce a new friend to Kotomi every day and brought her to Kyou. Later, Tomoya brought Kotomi to befriend Ryou. Ryou volunteered to tell Kotomi's fortune and explained that her relationship with her special someone with turn bad and that she will not be able to get a new friend the next day. Kotomi cried and ran away.
The next day, Tomoya started to enjoy studying. Tomoya, Kotomi, Nagisa, Kyou, and Ryou spends their lunch breaks at the drama club room fooling around. Kotomi was worried about Tomoya's studies and requested that they meet less often. They decided to meet every Friday. The following day, Tomoya couldn't find a new friend for Kotomi and refused to introduce Youhei as her friend. Kyou appeared and enjoyed groping Kotomi. Tomoya brought Kotomi, Kyou, and Ryou to the drama club room and had lunch with Nagisa.
The next week at the drama club room, they discovered Nishina playing the violin. Kotomi borrowed and played the violin horribly. She enjoyed playing and requested to borrow the violin for a week. She spent the next day practicing the violin. The following day, Kotomi visited Tomoya at his class and played for him, showing no improvement. Tomoya, Kyou, Ryou, and Nagisa dragged Kotomi to the drama club room. Ryou and Nagisa searched for a suitable place for her to practice.
On the way back, Kotomi's parents' colleague approached her. Tomoya and Kyou sent him away and Tomoya offered to escort Kotomi home. She declined, insisting that no one is allowed to visit her home. That Thursday, Nagisa and Ryou decided to hold a violin recital for Kotomi to enjoy her last day of borrowing the violin. Kotomi's violin recital was held at the schoolyard. She still played horribly but she enjoyed it.
The next day, Tomoya skipped the 4th period and had lunch with Kotomi at the library. She returned the violin and invited Tomoya on a date on the coming Sunday. The following day, Tomoya met Kotomi's parents' colleague on the way home. He explained that he is a fellow researcher of Kotomi's parents and wanted him to tell Kotomi that he still regretted what happened 10 years ago.
On Sunday, Tomoya went out on a date with Kotomi. Kyou, Ryou, and Nagisa followed them too. Tomoya found a violin on sale for 140,000 yen. He invited her on another date without the crowd. The next day, Tomoya and Kotomi went on a date at the school library. She announced that she enjoyed being with people and that she will attend classes. The following day, Kotomi was happy in class.
The next day, Nagisa explained that a bus had met with an accident. Kyou revealed that Ryou takes the bus to school everyday and was worried that she may be involved. Ryou then showed up safe but Kotomi violently broke down, remembering the loss of her parents. Kotomi was sent home and the teachers refused to explain her situation.
The following day, Tomoya confronted Kotomi's homeroom teacher. She revealed that Kotomi was offered a scholarship to study science in America. She turned down the offer when she started attending classes but she took up the offer again that morning. He demanded Kotomi's address and visited her home.
Tomoya found Kotomi's home and experienced deja vu. Kotomi's home wasn't maintained. Tomoya found his way to Kotomi's room by memory and found her sitting in the middle of a collection of newspaper cutouts. He discovered that her parents were killed in a plane crash. Tomoya's memory of his childhood with Kotomi came flooding back. Tomoya invited her to return to school but she didn't respond.
The next day, Kotomi didn't return to school. Nagisa revealed that she had planned a birthday party for Kotomi with Kyou, and Ryou and requested Tomoya to convince Kotomi to attend the birthday party. Tomoya then spent the next 3 days and all his money renovating her garden.
Nagisa, Kyou, and Ryou obtained the violin that Kotomi was playing and wanted to repair it as a gift for Kotomi. On the way to the music shop, a motorbike ran a red light and almost ran over Nagisa and Ryou and destroyed the violin. They begged the music shop owner to repair the violin.
Tomoya fell asleep after completing the garden renovation. He remembered details of his childhood with Kotomi. Tomoya remembered that he didn't attend Kotomi's 8th birthday because he couldn't gather a crowd for her. He was ashamed of his failure and decided to not show up on her birthday.
When Tomoya woke up, Kotomi was watching over him. She lamented her inability to regain her childhood and that she had lost her will to live. Tomoya confessed his feelings for her. Kotomi confessed that she feared losing the people she loved and Tomoya promised to always be there for her and to protect her.
Kotomi went back to school. Tomoya, Nagisa, Kyou, and Ryou explained that they had sent the violin for repair. Kotomi's homeroom teacher approached them and explained that her guardian, her parents' colleague, wanted to see Kotomi. He delivered her father's briefcase to her explaining that the local research facility received it the day before. It contained the bear plushie that her father bought for her. He explained that the briefcase was washed ashore in Africa and it traveled all over the world before reaching them.
He also revealed that the notebook that Kotomi burned 10 years ago was actually a toy catalog that her father showed him. The thesis papers were lost at sea. The briefcase also contained a letter from Kotomi's parents to her expressing their love for her. 3 months later, the violin was finally repaired and Tomoya, Nagisa, Kyou, and Ryou held a party to deliver it to Kotomi.