@Superbear:
If its a waste of time why did you entertain my statement in the first place? That's a bit nonsensical don't you think? Based on what you said about there being multiple sub-cultures in Japan I can't generalize his theme as being too Japanese. The Oni thing is a problem though we have the whole demon thing with Zoro, I can't budge on that one.
However a mentor character that is the best in his fighting style has no room to grow, no flaws to amend and as of now no solid dream to aspire to, also due to his attachment to the main characters is probably the next to be set up to die.
Do I want him to die? Will he? Maybe.
Come on now, how do we possibly know Jinbe is the best Fishman Karate user? There are certainly other Fishman like Namur/l in the New World and who knows what they are capable of? As far as we know Zoro is the greatest 3 sword user in the OP world, ultimately it doesn't mean much when other fighters of various styles outclass him in general speed, power and skill, same applies for Jinbe. Just because he may be one of if not the greatest FK user it doesn't mean there is no room to grow and judging by his performance against top tiers like Akainu in the war he has a lot of room to grow.
His flaw is obviously the being on land issue, he is better in water like Franky is better with Cola.
Demon? Him and Zoro? Great, then he Robin and Zoro can create the Demon Trio.
Jinbe has an extremely tragic past when tied with his people, for him to not see equality among men and Fishfolk would be very unlike Oda. And judging by the racism issue that has been a topic for around a decade now it won't be settled until the very end of the series with a not Jinbe.