Oh. Oh my god. Oh my god how many illusory walls have I missed?? Oh my god.
. . . I have about a hundred hours in this game and I think I just found out how illusory walls actually work.
I've mostly been playing this game blind and by sheer coincidence I had a wiki page open on Belfry Sol just to check something and I noticed a note about a hidden wall with the Black Knight Greatsword. I tried going to the spot and smacking every inch of the wall and couldn't find it. I'm not even using strength weapons, so I didn't need the sword, but I pulled up a video just out pure confusion and found out . . . hidden walls do not open when you hit them in this game . . .
The thing is that whenever you use a lockstone to reveal a hidden wall you can attack it open. It never occurred to me it was a separate kind of hidden wall, so in my head it never occurred to me I was missing anything. And yeah there's messages all over the place saying "hidden path" where nothing happened when I hit it, but trolling messages pretending to reveal hidden walls is just standard in other dark souls games so it never even registered as weird.
. . . I need to, uh, go back and check some places.