Characters that won't return in one piece

Narrative structure One piece it ensures that many characters are placed in scenarios where they can return to the story even after an extended absence. That being said, despite the opportunities this structure provides, there are a few characters that we likely won't see more of due to various circumstances. The exact reasons behind each character vary, with most united only in that, for better or worse, the story seems to have left them behind with no easy way to return. These characters have probably already made their last, if not one of their last, appearances in the series.

7 Nero

Probably dead

Nero was a member of Cipher Pol 9 (CP9) who only knew four of the six Rokushiki techniques that he did not learn in Tekkai and Shigan. Despite being shorter than most of his counterparts, he was able to hold off Franky for a decent amount of time. However, his own relative inexperience led to him being expelled after repeated failures. He was injured by Rob Lucci and thrown into the ocean during a storm known as Aqua Laguna.

There is still no official confirmation that Nero was killed, leaving open the slim possibility that he might somehow survive the storm. But even if that was the case, it still wouldn't translate into further performances. This is because Nero is essentially too unimportant a character to be definitively declared dead. He may be reunited at the end of the series alongside other characters who aren't killed off, but given his immoral nature, likely death, and relative unimportance, there's little to properly thrust him back into the series.

6 Hody Jones

Aging quickly

Hody Jones is one of the first serious villains in the post-Timeskip era One piece. He is the captain of the new Fish-Man Pirates and a blind follower of Arlong's ideals, knowing nothing of the people he claims to hate so deeply. He attempts to take over Fish-Man Island by force, using it as a springboard to carry out a vague plan to take over the world. However, for all his talk, it turns out that he and his crew are unable to take on even the top soldiers of Fish-Man Island without some support.

To do this, they constantly consumed energy steroids, which temporarily increased their physical strength. Although it led to premature aging, it gave them extra strength. However, these steroids not only didn't prevent them from being defeated, they ended up aging them beyond the point they could fight. Hody ate the most steroids and seemed to suffer even more than his peers. They were all imprisoned for their crimes.

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With their rapid aging and less story focus on the superior Fish-Man groups, there seems to be no reason for Hody and his crew to make a proper return.

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3 Enel

The man in the moon

For all the significant lore revealed during the Skypiea arc, it cannot be ignored that it takes place in a completely different terrain than the established blue seas seen throughout most of the story. This fact can be seen in the characters with little investment in the plot below, one of which is Enel. This self-proclaimed “God” seems largely content with his takeover, only frustrated by his inability to discover the Fairy Vearth, a legend told by the Birkan people.

After his loss against Luffy, and more importantly, his loss of power in Skypiea, he instead refocused his efforts on finding the Fairy Vearth. As it turns out, it was actually the moon. Enel eventually encountered automatons on the moon who were there to avenge their creator who died due to an explosion caused by aliens on the moon. Distraught, he said that the aliens were desecrating the Fairy Vearth, he kicked them out himself. After using his electrical powers to revive the defeated automatons, he discovers an army of them underground, as well as evidence linking the races living in the sky, and decides to rule the moon.

Considering his apparent contentment with this goal and the apparent lack of people negatively affected by it, it seems unlikely that Enel will return unless his moon base somehow comes into play.

2 Joz

In hiding

Jozu was a prominent member of the Whitebeard Pirates, being one of its 16 Division Commanders (specifically leading the 3rd Division). His Devil Fruit allowed him to transform his body into a nearly indestructible diamond at the cost of mobility. Its proper placement could prevent even a powerful slash from Dracula Mihawk, the strongest swordsman in the world, from causing any damage.

However, the deaths of his captain, Whitebeard, and crew mate, Ace, during the Summit War looked like it would spell the end for the Whitebeard Pirates. This was expanded upon during the Payback War where the remnants of the crew lost to the Blackbeard Pirates. They have been in hiding ever since, with the whereabouts of most members currently unclear.

It's not out of the question that Jozu could return, especially if what ever happened to the other surviving crew members becomes something to focus more on, but there doesn't seem to be much opportunity for that at the moment. At this point, it can be assumed that he is hiding, although it is not clear where exactly.

1 Gaimon

Guarding the island of rare animals

Gaimon is the man who fell into the treasure chest, and he supposedly is One piece author, Eiichiro Oda's favorite character. This fact, along with his hair, which has since grown out, gave him a strange but endearing appearance. He fascinated Luffy so much that the captain asked him to join the Straw Hat Pirates. Gaimon refuses because he has grown attached to the island's rare animals and feels an obligation to protect them.

He has since formed a relationship with the future Emperor Buggy when he was briefly on the island alone. A seemingly more permanent resident is Sarfunkel, a woman stuck in a barrel in a manner similar to his own predicament. The two seem romantically involved, due to her lovingly feeding him. The pair were two of many seen listening to Vegapunk's message, but this could be their final performance. Factors limiting Gaimon's involvement, aside from his desire to remain on the island, include his limited relevance and low combat prowess.