Kappei is a travelling teenager who recently arrived in town. He is cheerful, energetic, and has a morbid sense of humor. Kappei is physically weak and is trying to look for a job with a poorly-written resume. He has an androgynous look and it causes Tomoya and Youhei to mistake him for a girl, much to Kappei's dismay.
Kappei was orphaned as a child and he lived in an orphanage. The orphanage had a very gloomy and depressing atmosphere. Kappei discovered that he was good at running and he participated in races. He was very happy. One day, he was diagnosed with fibular osteosarcoma, preventing him from running ever again. He stood the risk of having his right leg amputated and he lost the will to live without the ability to run.
Kappei refused surgery and took a daily dose of codeine, a painkiller, to ignore the pain and tried to live a normal life.
Fujibayashi Twins' path
Kappei was first seen on April 21st when Kyou tried to ram Tomoya with her scooter. If Tomoya dodges to the right, Kyou rams Kappei and ran off. Tomoya wakes Kappei up and he ran to his interview, leaving his resume behind. Tomoya picked the resume up and decided to return it to Kappei.
The next day, Tomoya chose not to help Youhei carry his friend's television and VCR player to his room. Tomoya found Kappei and returned his resume. Kappei bought a can of coke for Tomoya but it sprayed on his face. Kappei wiped Tomoya's face with his handkerchief and left it with him. Kappei then rushed to the next interview. The following day, Tomoya met Kappei on the way to school and he returned the handkerchief.
2 days later, Tomoya and Youhei met Kappei. Youhei fell in love with Kappei. Kappei forgot who returned his handkerchief. Youhei confessed his feelings for Kappei but he explained that he was a guy. Youhei was heartbroken and was in denial. Kappei revealed that he has ran out of money and Tomoya sent him to live with Youhei.
The next day, Youhei confided in Kappei explaining that he was attracted to Kappei. After school, Kappei captured Botan and explained to Tomoya that he wanted to cook it. Ryou and Kyou approached them and Kappei recognized Ryou as the one who rescued him when he was rammed by Kyou once and they fell in love. Tomoya revived Botan and returned it to Kyou.
Kappei managed to find a job as a rehab assistant at the hospital where Ryou was working at. He revealed that he was hospitalized once and he greatly appreciated receiving rehabilitation. Kappei had found an apartment. Ryou has been visiting him and cooking for him. Youhei was sad that Kappei will be moving out of his dorm room.
Some time later, Youhei discovered a magazine that featured a story about Kappei. He sustained injury during a sprint race and he was diagnosed with cancer. Ryou failed to convince Kappei to undergo the surgery and requested Tomoya to convince Kappei. Tomoya and Ryou visited Kappei at the hospital. Kappei was happy to meet Ryou and he wanted to die because he sees himself as a burden to her if he loses a leg. Kappei was also thankful for having Tomoya as a friend.
Yusuke approached Tomoya and Ryou at the park. He listened to Kappei's story and suggested giving him a new meaning to life. The next day, Ryou expressed her desire to start a family with Kappei. Tomoya stressed the importance of a 2 parent family. Kappei then decided to undergo the surgery.
A few days after the surgery, Ryou revealed that she had found a hospital that could heal his leg without amputating it by using liquid nitrogen to kill the cancerous cells. They revealed that they also had proposed and is now engaged.
5 years later, Ryou was working as a nurse. Ryou and Kappei had been married for 3 years and he had been in rehabilitation since. The cancer was almost completely gone and he was about to undergo his final operation.