Here is where Oda probably drew inspiration for the Joy Boy character from:

“Encyclopedia of things that never were-1985”

— Joyboy —

“The West Indian character who personifies the human need to dance, sing, and jubilate. He is a relation of the Lord of the Dancers who inspires festivals in colder countries and it seems likely that he travelled to the Caribbean with an early shipment of slaves from West Africa.

Joyboy smiles perpetually at all the foibles and problems of mankind and cures human troubles by tapping out an irresistible rhythm on his drum. Whoever hears the music of Joyboy is compelled to dance and sing along until he or she has shaken the black cloak of despair from the shoulders.

Some jazz players claim to have captured Joyboy rhythms, but their efforts are a pale imitation of the dance frenzy which can keep humans dancing until they drop.”

So in this book they said Joyboy is a god of dancing, who is always smiling, is prevalent around Caribean region but originated from Africa. And isn’t it very telling, because the book’s Joyboy is exactly identical to One Piece’s Joyboy, almost like he took direct inspiration from this myth without even tweaking a bit.

Joyboy’s origin is from slave ships: Fit with the Sun God’s legend in One Piece that he’ll save slaves and bring freedom to them. Also, Joyboy is a figure from West Indian region – the region that always get associated with pirates.

Could Oda have been drawing inspiration from the myth told in this book? Please let me know your thoughts!