"The rumored return of a certain fellow is planned for 6.1 onwards." Yoshi-p from most recent live letter.

The question is probably who is this certain fellow? Since they are returning, I assume we already know them? Since fellow was a translation, was that a confirmation they are male?

Gosetsu tops my list, but could it be someone else?

I think we can best assess where the next part of the story is going once we know where the "rumored return of a certain fellow" has returned from.