is the commander of the Kamigari mercenary unit "Venus" and a former member of Maken-ki before it became an all-girls school. He is however the weakest member of Venus in terms of element level. Aki is hinted to have romantic feelings for him and it's even possible said feelings are mutual between the two. Akaya is a flirt around most of the female cast and is portrayed in the anime as a poser. He appears to be carefree as he finishes the rumor about someone trying to revive Yamata no Orochi (the eight-headed snake) with the words "or so they say" and a dumb smile on his face. It turns out that in reality, he is really serious about his work.
He initiates a change of Takeru's view of having to protect all girls, when he asks Takeru, what he would do, if a girl were to do bad things to another person. Akaya was one of last generation's Maken-Ki.