Oko is the president of the school's occult club. He is completely convinced that ghosts, demons, and black magic really exist, and wants to dedicate his life to proving that these things are real.
He is an awkward boy who is regarded as 'creepy' by the majority of the school, but he is actually quite harmless, and some people even find him to be endearing, as he is quiet and thoughtful. Perhaps Senpai will think that there is something charming about his unusual nature...