This is a really cool theory imo, what a fucking plot twist. It's worth a read at least imo:
https://www.reddit.com/r/Piratefolk/comments/1fbswc4
Robin was known as Demon Child too ofc.
Idk how Oda would justify all this, make it all come together but I love the idea of it.
Sleeper Agent Robin? I remember some people trying to hate on Jinbei just saying hes a sleeper agent/Kanjuro waiting to happen but more deliberate rather than brainwashed like Winter Soldier lmao.