There is still some time before we see the new season and all its deep mysteries, so fans should stay tuned for more information from the producers over the next few months. The people behind “Sherlock” have proven that they value their connection to their fans, so we have no doubt that they are preparing some additional press releases.
As for the future of the characters from the show after season 4, nobody seems to know for sure. As we pointed out above, the possibility for a spin-off is not out of the question, but it looks like fans would rather see more of Sherlock himself at this point.
It’s been implied that the writers are going to take some creative liberties with the character for this season, and will deviate from the canon established by Arthur Conan Doyle originally.
This could lead to the introduction of a new character, according to some fans, and that could be the missing piece to the spin-off puzzle. If it turns out that Sherlock has an unknown brother, it’s possible that he will be the main focus of the new show.
Fans won’t mind seeing something like this either, judging by their discussions online, although it of course depends on the exact nature of the new character, and how well he blends in with the overall setting of the show that’s been established so far.