Yoshino was living a normal high school life until he meets a Evangeline Yamato while he was visiting the grave of a family friend. His world is then changed as he decides to help his friend and save the world. Yoshino is calm and clever who is brave and strong. He is the type to make calculative judgements before making any decisions.

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 Hakaze 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.