I had this idea upon the introduction of Weevil in chapter 802 and Jack’s first full appearance in chapter 810, but it was further bolstered with the introduction of Yamato. Because the idea of another emperor, who isn’t Big Mom, having a child came up once again. So the speculation began again.
What first sparked this idea was the introduction of Weevil and the idea of Whitebeard having a biological son. Which I think is too good of a concept for it to just be a throwaway idea. I think Oda seeded that idea and completely destroyed our expectations because of how ridiculous both Weevil and his claim are.
But Oda covertly introduced Whitebeard’s “real” son one chapter before, burying the lead until his eventual reveal in chapter 810. That’s not to say that Weevil isn’t any less of a character and I’m certain Oda has plans for him in the future, but I think Oda also left us a clue in his appearance. Weevil, Whitebeard’s supposed son, has the same type of long braids as Jack does. I find it unusual that Oda would use a very similar design aspect in two completely unrelated characters that appeared only 8 chapters apart.
But Jack doesn’t look like Whitebeard.
True, but it can’t be expected of him to look like a mirror image of Whitebeard.
Much like how Ace doesn’t look exactly like Roger, Yamato Kaido or Big Mom and any of her children. But there can be some similarities found between them. Just like Yamato and Kaido’s horns and part of their hair. Katakuri and Big Mom’s pink hair, albeit different shades. We can compare Whitebeard and Jack’s heights and blonde hair. Although, Jack is taller and his hair is a different shade of blonde. I also think his metallic jaw mask is meant to hide more than just his jagged teeth but also any white facial hair.
But Jack is a Fish-man.
I believe Jack is a fish-man hybrid, although Jack’s vivre card from the data book categorizes Jack as a full fish-man. I really doubt this because of Jack’s lack of notable fish-man features (ie. fins, gills, webbed hands, abnormal skin color).
Jack looks like a normal human, by One Piece standards. His one notable fish-man feature is his jagged teeth a feature shared between two other fish-man hybrids Dellinger(half human/half fish-man) from the Donquixote Family and Big Pan(half giant/half fish-man) from the Foxy Pirates.
That being said, that statement in the vivre card data book could’ve been a mistake and we can see a correction further down the line, or it could’ve been left there intentionally until Oda further expands on it within the story. But that’s not it, he’s not just any old hybrid he’s Whitebeard’s son and the math adds up. Currently Jack is 28, which would have made him 26 pre time-skip, making Whitebeard 46 when Jack was born and around 45 when he was conceived. Now originally, my main claim as to Jack’s fish-man heritage was the fact that Fish-man Island was once Whitebeard’s territory.
But, Jack would’ve already been alive at the time (at about 4 years old) because Fish-Man Island didn’t become Whitebeard’s territory until the Great Age of Pirates which began 24 years ago, after Roger’s execution. But recently, more evidence was presented to us in Oden’s flashback when Oden reveals on Roger’s ship that he had been to Fish-Man island once before with Whitebeard, when he was still on Whitebeard’s ship(ch967).
Now Oden first joined Whitebeard 30 years ago in the story at which time Whitebeard would’ve been 44 and Oden didn’t join Gol D. Roger until 26 years ago making Whitebeard 48. Leaving Whitebeard and Oden’s adventure at 4 years between the ages of 44 and 48 with them having visited Fish-Man Island at some point between those 4 years, allowing for Jack’s conception and birth at around ages 45-46. Now, I don’t know what happened but I believe that Whitebeard met and fell in love with a mermaid and then just continued on with his adventure, expecting to see her again. But something must of happened to her between the last time she would’ve seen Whitebeard and after Jack’s birth, and I expect she met with an early demise. That would leave Jack an orphan with nowhere to go, with Kaido coming across him eventually. We can infer from chapter 920 and the vivre card that Jack was present in Wano and at the siege of Oden castle 20 years ago when he was only 8 years old. Which means that Jack was affiliated with the Beasts Pirates since at least 8 years of age.