The mentioning of Hachinosu got me thinking about a little thing that annoys me a bit. I think Hachinosu is funny, but also somewhat boring and uncool, because it's such a flat trope. Everyone there is just completely evil, leering drunks, ready to cut their own mother's head of and sell it for a drink. The slavers government send people they didn't like there, so shouldn't some really cool people have ended up there? Or just normal people who got in the way or committed the severe crime of being poor? Just like Australia.

Or maybe they have a three tier system: the work camp on the endless bridge where Robin ended up gets all the prisoners who are really just good honest people who got in the way of the government. Hachinosu gets all the cartoonishly evil caricatures of pirates. And Impel Down gets a carefully curated mixture of 70 % the same as Hachinosu and the rest are either ruffians with a golden heart who were led astray or secret revolutionaries, both of which end up in level 5.5 eventually.

I guess many fans like it, because they are like "finally a place with real pirates, like black beard". And by "real", they mean the caricature they mistake for historic pirates. But if you know anything about real pirate history in the Caribbean you know it's far from black and white.