Saya Kaito is the student council president and a student in Yandere School.
She's a member of the sports club (with Keishi Onozawa, Kumi Hideko and Makio Sono) so during lessons she wears the gym outfit and she runs around the camp. Anyway, she's slower than the others, and she stays quite far from the other members. Plus, when they're done and they go change or to the cafeteria, she stays in front of the baseball field using her cellphone.
Saya Kaito, as student council president, wants the best for everyone in the school.
She will ask Akari in Chapter 1 for a favor, to ask Eriko to meet her in the teacher's lounge after classes. If you proceed with this favor, she'll talk with Eriko about how poorly her grades have been.