like others have already said, the most logical would be big mom, law mentioned that when caesar was talking about his drugged candy, that it reminded him of someone
candy + reminded of someone + wanting to take down a yonkou = big mom
that would also coincide with kid already attacking big mom's ships (and therefore would be the perfect time and oppertunity for his re-introduction to the plot) , not to mention there has to be a continuation of the story soon as we all know big mom's tea party is in 4 days….
I'm right there with you. And some type of candy idea from Caeser would make the most sense, seeing as this: Law is sitting with Monet and Caeser, hears about the candy ideas on the kids from Caeser, immediately leaves to go find Luffy. It would just make sense that he needed something like that, plus that would help explain part of why he was working with Caeser in the first place. And the candies would just back the idea of Big Mom as well. Plus, when Law talks about the islands "important key that could throw the New World into chaos", it makes me think of the candy. And now that Law brought up the idea of an alliance against a Yonko, you can already tell that everything that's already happened in this arc(Monet, Brownbeard, Satyrs, Caeser, all that) will become pretty much irrelevant at the moment. But that's just my take on things.~