One Piece: What are the characteristics of the mysterious people hiding on the straw hat ship?

From the East China Sea to the New World, Luffy not only defeated powerful enemies one after another, but also gained many friends. So far, he has found nine. Not counting himself, he is still one short of recruiting ten partners. In fact, the Straw Hats have more than 10 partners, and there are always 4 mysterious partners hidden on the ship.

Luffy’s first partner was actually a panda. He witnessed every battle the Straw Hats fought, but never participated in one. He always shows up wherever the Straw Hats are, so it's obvious that he's been hiding in the Straw Hats' ship. Maybe his presence is too low and no one can find him. However, he did not deceive the photographer's eyes. He was photographed and a reward was issued.

During two years of practice, Franky not only created General Franky, but also secretly learned Baypunk's techniques. In a previous episode, Frankie accidentally saw the design of Baypunk's fruit-eating weapon, so two years later he gave Sonny a piece of fruit for everyone. There was really no sense of disobedience. Maybe this is Franky's murderer, who hid until the critical moment.

Hercules Wu is the owner, but his identity has always been a mystery, and his whereabouts are also quite strange. Luffy and his group came to the New World from the first half of the main line, but Hercules followed, as if he had all the information about the Straw Hats and could accurately know their location. Obviously, this can only be hidden on the ship, but the three main members of the Straw Hats did not notice his existence. He was really hidden deep enough.

Although Queen Sweetheart eats the fruits of nature, she does not know how to exploit them. She had to take off her clothes every time she used her powers, so she was so stupid that she could easily be defeated by Nami and put into a bottle. But Nami didn't throw it away, but kept it in the room.

Hercules is Wu’s master, let’s call him Master. After all, he taught Wu how to fight powerful plant seeds. You know, the entire Boeing Island is full of man-eating plants, so Hercules can survive in this extremely harsh environment and can even teach Wu how to survive. Of course, Hercules did not show much fighting power, but he was extremely mysterious, because he followed the Straw Hat Pirates all year round and secretly protected the Straw Hat Pirates, and no one in the Straw Hat Pirates discovered his existence. Hercules appeared in the Golden Emperor movie version, but Wu didn't notice him.