Yoshihisa Manabe has light brown, almost grey hair with brown eyes. He is normally seen in his school uniform which consists of a blue shirt with a matching blue tie and a white shirt underneath along with blue pants.
He is a depicted as a high school boy who often conjures up weird, and often perverted, thoughts in his mind, with Haruka describing him as such. He is also a bit of a dimwit, having an easy-to-read and transparent mind. He loves teasing Haruka by showing her perverted images in his mind with her mind-reading abilities. However, he is also a caring person who is easy-going and very friendly, shown when he was willing to befriend Haruka even though she was labeled as a freak by his other classmates and defended her when she was bullied by Hiyori.
Not much is revealed about Yoshihisa during the anime or even about his family life except that he and Hiyori go back quite a while, she often offering for him to come and visit her dojo. Before meeting Haruka, he was like any other teenage boy, going to meals with his friends and hanging around with them.
Manabe cares very much for Haruka. When she was getting bullied by Hiyori and her friends, Manabe stood up for her. He promised to stay with her forever, no matter what happens. At one point, Yuriko, president of ESP club makes Haruka and Manabe go on a date. Until the final episode he never directly says he loves her. On the final episode, when Haruka confesses to him, he says he'd "always, always loved her" and he "loves her like crazy". Manabe likes to fantasise about Haruka, much to how much it embarrasses her.
Hiyori and Manabe go far into the past. At some point, Hiyori invites Manabe to her dojo. Hiyori is in love with Manabe, although she likes to see Haruka and him together.
Yuriko is the president of the ESP club. Manabe and her do not have a close relationship, besides being members of the same club. Yuriko enjoys teasing Haruka about her relationship with Manabe, and she is the one who makes them go on a date together.
“Look, Kotoura. Whether you can read minds or not, people who want to leave are going to leave- But not everyone is like that. So let's try this, Okay? I’ll stay with you. No matter what happens, I won’t leave. How about it?"
Out of all the main characters, Manabe is one of the most static in terms of character development- He changes very little throughout the show.
Out of all the girls in the show, Manabe fantasises with Kotoura the most.
Manabe has mentioned he has an older brother, but it was from Kotoura's mind reading.