Yoshioka is an old-school gentleman who is almost too gallant for the modern day. When a lady is in danger, he rushes heedlessly to her defense, wielding machetes or even garden rakes as though they were samurai swords. This, along with a desgree of shyness, is why he refuses to admit that he is attracted to Kotomi; he is a lowly boiler operator while she is the owner of the bathhouse and a successful white-collar worker. From Yoshioka’s perspective, a man of honor with his social status could never besmirch someone like Kotomi with even the slightest of advances. Still, his infatuation makes go above and beyond the call of duty in everything bathhouse related, even if that means braving the dangers of the Crater to recover rumored samples of otherworldly fuel or facing possible embarrassment by being part of the latest promotional gimmick Kotomi thinks up.
Yoshioka takes his job at the bathhouse as seriously as he takes his adherence to traditional manners. He is constantly making sure the bathhouse’s boilers are in tip-top shape and keeps to the highest of safety standards when dealing with fire—even if he does occasionally lose control of the volatile alien fuel and blows the door off the boiler room. Yoshioka enjoys the fire-starting aspects of his job just a little too much, but this is kept mostly in check by his keen sense of responsibility and a desire to serve as a role-model to kids and possibly even adults.

While the series shows very little of Yoshioka’s life away from the bathhouse, but what we do see indicates that he is a very fastidious bachelor. His single room apartment appears to be neat and clean from what we see during the brief we get glimpse of it during the night of the storm in Episode Thirteen. In  Episode Nine, we see him arriving to work with a bento box that has been carefully wrapped in a carrying cloth. All in all, Yoshioka seems like he might still be a “catch” if he should meet the right woman, or if he should set aside his devotion to the separation between social layers and start to court Kotomi.

Out of the main characters in the series, Yoshioka is the only one who doesn’t experience a crises of some sort, even if he shares Kotomi’s deep sorrow over the grim future of the bathhouse during its money-losing months. He his happily stoking the bathhouse boiler at the beginning of the summer portrayed in NieA Under Seven, and his life seems as though it will continue as it has for the past two decades.