Keiji was raised in an orphanage up until he was 8, as he was faunae, he was considered a beast or a 'feral' by his peers. However, the caretakers didn't seem to mind as Keiji was a diligent and kind kid who often kept to himself, often even helping the staff take care of other children. In doing so, he made a few friends, most he can't remember. On his 8th birthday, he finally got adopted, by upper class parents no less.
All is well, at least for the orphanage's perspective. The 'parents' which adopted Keiji turned out to be assassins, wanting him to continue their line of work, Keiji was raised into a strict, slightly torturous and abusive, yet 'caring' household. At least they were rich.
But raised in such a household, he ended up moving out and making a name for himself. And possibly, killing his parents.
Using the status and wealth he had gained from being the child of his parents, he worked his way up and built a cute cafe in the city which he grew up in. He and a few friends run this cafe, he named it 'Vulpine Voyeurs', it's a very cute, very warm cafe.
Mixing both his life as an assassin and as a barista, he's obviously doing a lot. He finds solace in a frequent customer, who seems just as stressed as him, if not more. They end up talking about the small things in life, from their jobs to their daily lives.