Just a theory of course, but a lot points to it. First his name is Sakazuki (japanese sake cup).
Second he looks like a Yakuza and even has a sakura tattoo on his torso (though he is based on an actor who played yakuza/ronin and generally tough guys in japanese movies, but still). He also likes bonsai.
Third when someone starts to talk about Wano or asks him about Wano he tries to change the topic or just outright says something like: this isn’t our buiseness or it isn’t in our jurisdiction.
Like he tries to keep Wano isolated from entire world at all cost. Possibly because he illegaly left Wano like a few other citizens (Oden etc.) and has some kind of a secret/dark past tied to Wano that he doesn’t want to reveal.
What do you think?
*Theory by Corax