I’ve seen some people theorize that somehow Mother Caramel is still alive and living in Charlotte Linlin, and while I don’t necessarily think this is true, I thought I would provide the “evidence” I’ve found.
One, to start off with the question of how Big Mom got her Devil Fruit powers is still a bit up in the air. We assume that she gained them by eating Mother Caramel, but we don’t have any definitive proof that eating a Devil Fruit user would give you their powers. In fact Oda has actually answered what happens if you eat a Devil Fruit user all the way back in SBS Vol. 16:
-Q:”If I eat Luffy, will I become a rubber-man?” -Oda:”No, you’ll get food poisoning.”
This seems to clearly state that Big Mom should have gotten sick, not gained Caramel’s powers.
Second, there is an obvious parallel between Moriah’s fruit and Big Mom’s fruit. So while there is supposedly a rule against putting souls into living things, similar to how only Moriah can truly make shadows stay in a host, I think the user of the Soru Soru no Mi is the only one who can put their soul in another living thing, and can transplant their soul into someone else, in the process killing their old body.
Third, it is very clear that there is some kind of bipolar-ness going on with Big Mom during her hunger pangs, but perhaps the most interesting thing to me, is the fact that her Soul Powers are seemingly weakened. This makes sense if you consider that during this hunger pangs, Linlin’s soul takes more control and Caramel’s is stifled.
*Theory by MugiwaraVicki