I've been thinking, what if Blackbeard had the mythical zoan of the Kraken or Davy Jones? So, like, like Vegapunk said that fruits come from the imagination — probably mythical beings don't exist, they're just legends, or they were beings that existed and were exaggerated. It's entirely possible that one day they saw a giant squid or octopus that did something silly like release a huge amount of ink or attack ships and sink into the ink itself. But because of fear, the darkness of the ink and the grandeur of the creature, the legend of a giant squid may have grown into a Kraken. And in these legends, the octopus' ink slowly turns into a literal black hole due to popular imagination. A fisherman's story is the same as a pirate's story... the guys keep getting bigger, and following this logic the same could have happened with Davy Jones.

Or perhaps Davy Jones could have been a man who had a Zoan squid/kraken. And the story only grew in the popular imagination until Davy Jones himself became a mythical Zoan just like Nika — probably the powers of Nika's fruit were altered over the years by the popular imagination. And so the World Government tries to hide the existence and myth behind what people believed; faith and stories change the mythology and therefore change the fruit. And the connection with Blackbeard — because, do you know who sleeps little, almost nothing? Octopuses. Do you know who has three hearts? Octopuses. Do you know who can emit frightening darkness? Octopuses. Do you know who is known for their intelligence and for escaping situations with their brains? Octopuses. All of this fits Blackbeard. “But there is no marine animal Devil Fruit” — there is: the Raku Raku no Mi, which was eaten by one of the SWORD members; is a sea otter Zoan. It has been said that there is no such thing as rubber fruit. But what if it doesn't exist because the person who had the original rubber fruit was the warrior Nika? And from it was created the myth of the God Nika, which in the popular imagination over the years was altered until he was able to transform things into rubber and the rubber fruit ceased to exist? There Joyboy ate the fruit and perpetuated the myth. Just as it could have happened with Davy Jones eating the Kraken fruit until his fruit literally became Hito Hito no Mi, Model: Davy D. Jones, who has the powers and hybrid form of Kraken.

Oda, in an SBS, already showed Davy Jones' face and he didn't look like an infamous or evil pirate — perhaps the myth is what made him infamous, or the fruit. Maybe he was just an ordinary pirate or an ordinary man who, over time, by mythology or by the will of the World Government, became something infamous and evil. Because Oda drew the MAN Davy D. Jones, but he didn't draw the MYTH Davy D. Jones that people and the World Government tell.

Davy D. Jones theory