Saigusa's first appearance in the series is as a minor character in a short story in The Case of Takafumi Yokozawa 3. He works for Animate and shows Takafumi Yokozawa around a new Animate branch in Ikebukuro. It starts to rain and Yokozawa is caught without an umbrella when Tezuka comes in and offers Yokozawa the umbrella he was just using. Yokozawa declines since then Tezuka would be without an umbrella, but Tezuka says he'll just take Saigusa's umbrella. When Saigusa asks what he's supposed to do then, Tezuka teases him that he could just have his girlfriend pick him up, which seems to make Saigusa uncomfortable. Yokozawa accepts Tezuka's umbrella and leaves.
Saigusa's relationship with Tezuka is explored in the novel The Case of Animate.
- Saigusa's name has been inaccurately translated as "Saegusa".
|Sekai-ichi Hatsukoi characters|
|♥||Masamune Takano||Chiaki Yoshino||♥||Yoshiyuki Hatori||Shouta|
Kanade Mino •
Ryuichiro Isaka •
Kaoru Asahina •
Kazuma Henmi •
Yasuda Gou •
Sanae Hoshino •