u/ColinHalter

So I fully understand that Shannon/Kannon/Beatrice are all just personality fragments of Yasuda, but how did they transition from being known and referred to as Yasu to Shannon by the staff and residents of Rokkenjima?

The way I currently understand it, Shannon was purely a figment of Yasuda's imagination until Yasuda "became Beatrice" and left Shannon on her own (or in reality, when Shannon took over as their primary persona).

What I'm not clear on is how they managed to go from being known by their true identity to immediately going by Shannon as an employee on Rokkenjima. Natsuhi seems to know all the members of the servant staff pretty well and runs a tight ship, so I think it's unlikely that they could just sneak into the shift rotation like that. Plus Yasu was a pretty special employment case and was well known especially by Natsuhi. It's also not easy landing that job from the Fukuin house, so I imagine "Shannon" would have had to go through that process of being selected again?

I can understand how they could have managed to split off and be both Shannon and Kanon at once, but I'm not sure how they pulled off disappearing as Yasu and just showing up the next day as Shannon unless the whole staff knew it was the same person and was just cool with it. I know Genji knows Shannon's true identity, but Natsuhi clearly doesn't (as demonstrated in EP 6 by "the man from 19 years ago")