It was mentioned in Drama CD that his parents gave him the name Saika, so that his life could add colour to others. It was mentioned by Yui that Saika was in the same class as Hachiman during the first year of high school. Hachiman fails to recollect this. He is first introduced in the series when he asks the Service Club to help him improve his tennis skills. Since then, he is a recurring character and became an unofficial member of the Service Club's activities. The former president of the club retired and Saika was nominated to be the next president for his dedication as mentioned in Volume 7.5. Saika was mentioned to practice tennis when ever free time presented itself, even during lunch break.
Once when he visited a game arcade with Hachiman, he wanted to try the photo booth which the maintenance men didn't object to since the booth was for couple and girls, indicating that he mistaken Saika to be a girl and a couple with Hachiman
Just like Hayama, he has his set of fans; especially girls. After the tennis court showdown of Hachiman, Yui and Yukino against Hayama and Yumiko, he became more determined and dedicated in tennis.
Saika is introduced in Volume 1 Chapter 6. He sees Yui and Hachiman talking during his lunchtime tennis practice and comes over to talk. Yui introduces him to Hachiman, who mistakes Saika for a girl at first. A few days later, Saika partners with Hachiman for gym class for tennis. He asks Hachiman to join the tennis club. Hachiman declines. After school, Saika requests that the Service Club help him get better at tennis.
During practice one day Saika hurts himself. Just then Miura and Hayato show up and challenge Hachiman to a tennis match over who gets to use the courts to help Saika. Saika is injured cannot play, so he referees the game. After Hachiman and Yukino win the game, Saika thanks Hachiman.
Saika inquires about Hachiman's group for the upcoming workplace tours, but Hachiman doesn't get his hints until after Hayama's "chain e-mail" request when he confronts Hachiman and says he wants to be in his workplace group. Hayama, Hachiman, and Saika decide to be a group together.
Later during a study session, Saika hears Taishi's request to help his sister, Saki. Saika offers to help the Service Club with the request. Saika helps with all of their attempts to talk to Saki until they go to the Royal Okura Hotel. He does not have proper dress attire so Yukino sends him away.
When Yui leaves the Service Club because of what Hachiman said at the workplace group tours, Hachiman is feeling guilty. Saika catches him after school one day and offers to hang out before his night lessons for tennis. The two go to an arcade and run into Zaimokuza, who shows them around "his domain". Saika wants to try the "purikura" (photo booths), but Zaimokuza tells him its only for girls and couples. However, due to his feminine appearance Saika gets Hachiman and himself through the guard while Zaimokuza is chased away. After the outing Saika gives Hachiman a photo of them and states he felt like Hachiman was acting funny, but is glad to see him feeling better.
Volume 3 Drama CD
Saika is invited to Yui's birthday party at karaoke. He leads the toast and offers to cut the cake. Totsuka reveals he has Type A blood. He gives Yui a hair-clip as a gift. During karaoke he sings with Komachi.