After thinking about potential One Piece ideas i realised that I have never read a One Piece fanfiction where the MC was apart of the Mink Race.
So when I decided to make MC a mink i was thinking if there are any characters from other verses that you could base the MC on and I found my answer.
Tai Lung from Kung Fu Panda.
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(I just want to say before I start that my knowledge on One Piece isn't that great seeing as Im just at the part where the strawhats met up after the 2 year time skip)
You can make it that the MC is the last of the Snowy Leopards that were once a very influential race among the minks
As one of the last of his kind he was caught by slave traders to be auctioned off. Thats where our MC takes over the body and ends up escaping from the slave traders.
The MC was reborn with all of his memories intact along with the memories of Tai Lung from the Kung Fu Panda movie.
With his and Tai Lungs memories he decides fo train himself, he uses his memories to train his haki and tai lung memories to train the Leopard Style of Kung Fu which focuses on speed and angular attacks while focusing on elbow, knee, low kicks and leopard punches.
Since the MC is a leopard you should make sure that he uses that to his full advantage by using his claws, tail etc...
I think it would be cool if the MC joined either Whitebeard Pirate's or Red Haired Pirates to gain experience in fighting and then later on leave the crew to make his own crew. (Or jusg join luffy like most other fanfics whatever u feel like.)
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Things to consider...
The way my idea works is that the MC is a martial artist, so it would be best if the MC didn't use weapons and didn't have a devil fruit since i feel like a devil fruit doesn't fit the MC.
I actually hope someone uses this idea sinfe we rarely see a One Piece fic where MC focuses on martial arts since most focus on devil fruit powers or swordsmanship