10 horrifying One Piece storylines that fans don't talk about enough

The various One Piece storylines found within the 1100+ officially released chapters of author and illustrator Eiichiro Oda’s manga series are one of its biggest strengths. Seemingly every character, no matter how important or unimportant, always receives some sort of focus, revealing their motivation, characterization, and goals.

However, some One Piece storylines are much darker than others for a variety of reasons. Some touch on horrifying real-world atrocities and hit too close to home, while others focus more on the rules of the series’ world and how a scant few scarily break them with ease. In either of these two cases and everything in between, it’s clear that there truly are some horrifying One Piece storylines.

Bringing the dead back to life, a genocidal World Government, and more horrifying One Piece storylines

1) Doctor Hogback and Victoria Cindry

Hogback (left) and Cindry (right) as seen in the anime (Image via Toei Animation)

Unsurprisingly, one of the most horrifying of all One Piece storylines comes from the spooky Thriller Bark arc. In the arc, fans are introduced to Doctor Hogback and his assistant, Victoria Cindry, who seemingly hates him. Fans learn why upon learning of their origins, with Hogback originally being an obsessed fan of Cindry, who was a famous actor and his patient. He proposed to her, but she rejected him and died shortly after.

Enter Gecko Moria and his Shadow-Shadow Fruit, which allowed Cindry to be revived in her original body but with a completely different personality. This led Hogback to become spiteful and abusive, saying he only cared for her beauty and had no use for a personality that rejected him and prompted him to physically abuse her. It’s a truly horrifying storyline, both in its more fantastical and more realistic and grounded developments.

2) Rob Lucci's Dark Justice

Lucci as seen in the anime series (Image via Toei Animation)

Rob Lucci’s Dark Justice is another horrifying One Piece storyline, yet for a very unique reason. His alias “Massacre Weapon” touches on this subject, with his Dark Justice turning him into someone who viewed no sacrifice as too great for the sake of order. This is best exemplified by a mission he was sent on as a 13-year-old, where 500 soldiers of a kingdom were taken hostage by a pirate crew whose captain demanded to be the new king.

Rather than rescuing the hostages, Lucci infiltrated their holding ground and killed every single one of them before mercilessly slaughtering the entire pirate crew, captain included. Lucci justified this by saying the soldiers were weak and unable to protect their kingdom, thus making them acceptable losses per his philosophy.

3) Vinsmoke abuse

Vinsmoke Judge as seen in the anime series (Image via Toei Animation)

While Sanji’s abuse specifically comes to mind here, his father Judge, in reality, abused all of the Vinsmoke children in one way or another. This also makes it one of many horrifying One Piece storylines by nature of how grounded in reality it is in a sense. This especially applies to Sanji, who suffered emotional and physical abuse at the hands of Judge and his siblings by having his dreams made fun of and being locked inside a dungeon with an iron mask on.

However, the other Vinsmoke children were abused as well, having their genetics manipulated and personalities guided into becoming emotionless, heartless killing machines. This is especially shown during the Whole Cake Island arc, where none of the Vinsmoke children are scared to die while Judge is absolutely terrified at the thought.

4) Big Mom’s implicit cannibalism

Big Mom's origins are easinly one of the most harrowing One Piece storylines (Image via Toei Animation)

Also during the Whole Cake Island arc, fans finally learned of Big Mom’s backstory, which is undoubtedly one of the most horrifying One Piece storylines. Born an abnormally large human, Charlotte Linlin was abandoned by her parents and eventually adopted by Mother Carmel, a nun who actually sold her orphans to the World Government as future soldiers.

Likewise, she put up with all the trouble Linlin gave her (even murdering one of Elbaf’s leaders) due to the payday she’d get from selling her off. However, she never got the opportunity, as it’s heavily implied that Big Mom ate Mother Carmel and the other orphans in a hunger pang frenzy one day. It’s one of the darkest ends any character has ever met in the series thus far, and further speaks to how monstrous Big Mom is.

5) A genocidal World Government

The Oharan Genocide is one of the most horrifying One Piece storylines (Image via Toei Animation)

With the Egghead arc’s introduction of the Buccaneer race, fans now know of three different clans who were seemingly targeted for genocide by the World Government. While this is confirmed for the Oharans and the Lunarians, it’s heavily implied for the Buccaneers by nature of Saint Jaygarcia Saturn’s words to Bartholomew Kuma in God Valley. Likewise, the sheer number of genocides makes the topic one of the most horrifying One Piece storylines.

6) Caribou’s Swamp-Swamp Fruit

Caribou seen using his Swamp-Swamp Fruit in the anime (Image via Toei Animation)

While not a full-blown storyline in and of itself, Caribou and his Swamp-Swamp Fruit have played a major role in the series throughout the entirety of the post-time-skip section. Likewise, despite playing such an important role, fans still have no idea what being inside the swamp as a sentient person is like.

One would assume that, since food doesn’t spoil in the swamp, that time doesn’t pass. Yet in this case, are those sentient beings absorbed into the swamp forced to sit idly by for what seems to be an endless eternity without aging or growing hungry? Are they able to move, speak, or even think while absorbed? These questions and many, many more make the Swamp-Swamp Fruit in and of itself one of the most horrifying One Piece storylines.

7) Florian Triangle shadows

Thriller Bark (foreground) and the shadows (background) as seen in the anime (Image via Toei Animation)

At the end of the Thriller Bark arc, one of the truly horrifying One Piece storylines is introduced in the form of amorphous, monstrous blobs seemingly occupying the area. Nothing is known about them aside from them presumably being responsible for the hundred-plus ship disappearances the area is known for on a yearly basis.

While there’s much about the series’ world that’s unknown, this is truly a mystery for which there is no knowledge. All that’s known is that these monsters have red eyes, dwarf Thriller Bark, and remain hidden by blending in with the fog. One theory is that they could be inspired by Umibozu and somehow related to Imu, who also has red eyes and is also seemingly inspired by the Umibozu yokai legend.

8) Celestial Dragons’ Native Hunting Competition

Celestial Dragons seen walking with a slave in tow (Image via Toei Animation)

Unsurprisingly, one of the most harrowing One Piece storylines is also one of the most grounded in reality and likely to happen. During Kuma’s flashback in the Egghead Island arc, fans got their first taste of the events at God Valley. In the process, they learned that the Celestial Dragons were there to host something called a Native Hunting Competition.

Essentially, they treated the natives of God Valley and whatever slaves they brought with them as game in a hunting competition, competing for points based on each of their kill counts. It shows the depravity of humanity by reminding viewers that similar events occurred in real life. It’s a truly horrifying scene, which emphasizes the themes and morals Oda presents in his series.

9) Caesar Clown’s child gigantification research

The children seen suffering from the withdrawal of Caesar's drug (Image via Toei Animation)

The Punk Hazard arc is the origin point of many post-time-skip One Piece storylines, many of which aren’t that horrifying in and of themselves. However, one truly disgusting story to come from the arc is Caesar Clown’s child gigantification research. Essentially, with the help of Vergo, he was able to kidnap children to use on research being fueled by Big Mom regarding the creation of Giants.

What’s truly despicable is that Caesar lies to the children, convincing them they’re sick and that curing them will save the world. In reality, he gives them drugs that make them physically sick and mentally frail from withdrawal, to the point where they’re threats to others and themselves. Again, this storyline is so harrowing because of how grounded in reality it can be, emphasizing the potential for evil that both Oda’s world and our own have.

10) Blackbeard having two Devil Fruits

Blackbeard wielding two Devil Fruits as seen in the anime (Image via Toei Animation)

In and of itself, Blackbeard having two Devil Fruits isn’t necessarily one of the most horrifying One Piece storylines. What makes it so horrifying are the rules of the series’ world, which state that anyone who tries to eat two Devil Fruits dies immediately in a horrific way. It’s this deviation from the natural order combined with the buildup of Blackbeard as an abnormal and maybe even inhuman entity that makes the plotline so harrowing.

Likewise, exactly how Blackbeard is able to do this is still unknown in the contemporary manga series, further adding to how horrifying the detail is. While it’s difficult to say what the reason is, it’s easy to assert that the reveal will only make Blackbeard’s origins, character, actions, and motivations even creepier and alienating than they already are.

In summation

Given the nature of the series, there aren’t many truly horrifying One Piece storylines in the most traditional sense of the word. However, with a more liberal approach to the term, it’s clear that many different One Piece storylines of all shapes and sizes can qualify. That being said, those that truly stick to the word’s traditional definition are some of the most harrowing in the entire series.