Spoiler!Despite his good guy facade; Yoshino is actually very manipulative and deceitful as explained by Mahiro in the countless times he betrayed him; It is due to this nature that Samon asks Mahiro to kill Yoshino in fear that he will manipulate Hakase to alter the world to his choosing
He breaks down after Hakaze pushes him on showing his real emotions and to stop hiding everything from everyone else.
Spoiler!In the final chapter we see him passing his university entrance exam with Mahiro.
He tells Hakaze that there are lots of other guys out there better than him but Hakaze still won't give up on him.
Seiyuu: Uchiyama Kouki