Watashi's personal assistant. He never talks, but Watashi is able to understand what he is trying to say just by looking at him.
In Episode 8, it's revealed that Assistant can speak.
At the end of the novel it's revealed that Joshu-san is one Joshua-san, the final remaining human that the fairies have attempted to communicate with via Watashi and her grandfather, both sleeper fairies along with every other character in the story.
