While re-reading the Succession War Arc I noticed the particular framing/paneling in Chapter 370 that leads me to suspect that Satobi is the Silent Majority user.
For instance in this spread page showing all the participants Satobi is standing right next to Yuhirai and Shedule (2 of the 4 nen users Furykov spotted), Barrigen (the target), and Loberry (the one possessed). Proximity isn't a smoking gun but it's suggestive.
When Lobberry yells out, bringing attention to the Marionette, Satobi's reaction isn't shown. He's between Yuhirai and Shedule, but he's deliberately cut out of the framing between the bottom middle panels. I think this was an intentional choice and implies that Satobi already knew what was happening and thus his reaction wasn't shown.
The second panel on the chapter's first page shows the significant characters of the chapter. When the class starts the Marionette framed right next to Satobi; along side Loberry (the one possessed), Barrigen (the target), Belerainte (the Hunter), Yuhirai and Shedule (2 of the 4 hidden nen users Furykov spotted).
The framing of characters in Togashi's stories are very deliberate and thought out. So when Satobi is posed right next to Silent Majority in multiple panels it probably means something, or is a red herring.
Case in point, these panels clearly imply that Satobi is the Silent Majority user. The Silent Majority User's internal dialogue is framed right next to the Satobi and the Marionette in the same panel.
The evidence I have shown clearly demonstrates the meta-contextual framing of Silent Majority implying that Satobi is the user, or it's all a deliberate red herring on Togashi's part, using the manga's composition to cleverly mislead the readers.
Idk, I made my point, so I would want to hear your guy's thoughts. I fuck'n love this murder mystery in the arc. Like the way its' written with just enough clues for speculation is one of the most compelling parts of the Succession War, in an Arc bursting with compelling story lines & speculation. I'm super excited and geeked the fuck out for the new batch of chapters, and I hope I see you guys here speculating alongside the characters as the story goes on.