u/Gen_the_Owl

I think that shadow six is regular six’ innocence. At the beginning of altered echoes, we see six being taken away by The Thin Man. after he takes six, she is warped into a monster. I’m pretty sure the signal tower is entirely different depending on who’s inside. The main thing that was keeping her trapped, was the music box. Because she’s had the music box for so long, it’s so nostalgic to her, it traps her there, trying to relive all the good memories, before being chased by psycho teachers and such. The ST uses her overwhelming attachment to keep her trapped here, and turns her to a monster. This makes it so she’s unable to move on with her life, and moving on would include leaving the ST. After the music box is broken, since it was the only thing keeping her from moving forward, she reverts to normal, but only physically. She still experienced all that. She’s spent all that time obsessing over that one little thing, the one thing that ever made her happy, and then mono just destroys it. So now, she drops him. The ending of Altered Echoes is probably the same thing happening at the same time, but just being relived through the eyes of shadow six. Now, along with mono, the music box, (only this time figurative) gets dropped and shattered, with shadow six being “born”. This happens at this moment because, this is definitely the biggest and worst thing she’s done; killing a child. She changes completely, and turns to an unfeeling ghost, while her innocence leaves. In little nightmares, she didn’t eat that Nome because she just suddenly turned big evil, she did it because it was significantly more filling than a puny sausage, and was simply too full to eat the sausage afterwards. And she remember how we all saw shadow six and went “ooh!! Oh no!! Big spooky evil six!” Nope. She’s actually watching in DISGUST at what her future self has become. But six isn’t evil, and she never was. But after her best friend did something horrible to her (even if it DID save her life), she “killed” him, causing steep downfall of her ability to be sympathetic. And you know all those shadow children in ln2? Those are also the lost souls of the adults. As Mono collects them, he gains the memories of their past. And I’m pretty sure they didn’t actually meet up or anything in the secret ending, she was just following regular six, as she does for the rest of time. I’m pretty sure the entire game is just shadow six reliving memories.