We like to joke that OP is a goofy pirate manga and “despite being dark, it’s usually at a surface level be the story is primarily made for kids.”
And yet we’ve still gotten implications of sexual assault/abuse with the traumatized Boa sisters, actual sexual assault ending in pregnancy recently with Ginny, CONSTANT slavery which happens so often it gets undermined but is horrendous when you think about it, biological warfare, several genocides in the story, a damnear biblical witch-hunt of pregnant women and infants suspected of being Roger’s kid, an island of forgotten people living as toys and watching their families go on without them (Dressrosa), cannibalism, child trafficking and experimentation/drugging, lmao at this point we got satanism with Brook’s timeskip and Saturn, necrophilia (Hogback and Vasco Shot), and probably some things I’m missing.
I get that OP maintains its upbeat veneer most of the time but if you actually look at the world, it’s much darker than most if not all shonen worlds.