Kasahara is very reliable and mentally strong. He also is the hardest worker, and takes a lot of time doing weights and film studies.
His grandmother takes care of him, but since she got sick, he is going to leave Seiseki and go to another school closer to her home in order to take care of her. He was not named in the seventeen-strong squad for Inter-High, his spot was given to Tsukushi instead.
He is known to be dependable and being a clutch performer, but was known to take a 'safety first approach', meaning he cannot be a game changer.