Summary
Quick Links
Despite being the primary power system ofOne Piece, at times it doesn’t feel like every aspect of the mysterious abilities is explored in a substantial way. Namely, the weaknesses of the system, the fact that Devil Fruit users are cursed by the sea and drained by its energy, aren’t brought up nearly as much. This is especially true with the modern introduction of Haki, which at times, completely overshadows some aspects of Devil Fruits inOne Piece.
Interestingly enough, although many characters use Haki to fight againstOne Piece’sDevil Fruit users, there is another way to handle foes with this mysterious ability; through the use of Seastone weapons. While this powerful mineral is able to nullify even the strongest of Devil Fruit users, it has rarely been used throughout the series in any meaningful capacity. Seastone weapons do exist in the world ofOne Piece, and it’s a shame only a handful of characters actually utilize them.

Seastone Weapons In One Piece Are Rare
Only Smoker Uses These Weapons Substantially
InOne Piece, one of the primary users of Seastone weapons is theOne PieceVice Admiral, Smoker. Since his introduction, Smoker has always used the Nanashaku Jitte, a jitte that has been specifically tipped with theOne Piecematerial, Seastone. By using it with the range providence from his Devil Fruit, the Plume-Plume Fruit, Smoker can use the Jitte to drain Devil Fruit user’s energies and damage characters, like Luffy, that he normally wouldn’t be able to hurt at all.
The tip of my jitte is made of a substance known as Seastone. - Smoker

Overall, outside of Smoker’s Jitte, there are only a few other examples of Seastone weapons inOne Piece. This includes a Seastone spear that is possessed bythe Worst Generation member, Capone Bege, Wyper’s skates in Skypeia, and the Seastone nails from Wano. With these four examples, and only two of them being weapons, it seems that the idea of Seastone weapons never caught on. However, although the idea of Sestone weapons sounds good on paper, they may not be as effective as fans might expect.
Seastone Is Hard To Use In Intricate Crafting
The Difficulty May Make Seastone Not Worth The Trouble
Firstly, it is implied duringOne Piece’sWano Arcthat Seastone is a fairly difficult material to work with. Although nothing is directly confirmed, forging weapons out of the material may be a difficult task that only the best weaponsmiths in the world ofOne Piececould handle. Although making something like a Seastone net or handcuffs is much easier, trying to create something as refined as a sword or bullets is going to take a lot more work.
In addition to being tedious, with the ability to utilize Haki, making Seastone weapons hardly feels like a worthwhile endeavor. For most fighters inOne Piece’sNew World, Haki is the primary means of power and getting stronger. Additionally, Haki bypasses Devil Fruit abilities, which is one of the few advantages a Seastone weapon has. Although they don’t drain the target of their energy, the sheer power that comes with Haki makes this almost unnecessary.

Seastone Weapons In One Piece Could Be Used With Haki
While Haki Is Stronger Than Seastone They May Be Stronger Together
While Seastone weapons seem obsolete due to their difficulty to forge and the fact that they’re overshadowed by Haki, they still do provide some tactical advantage in combat. Namely, as Smoker showed during his time inOne Piece’sPunk Hazard Arc, these weapons can be used in conjunction with Haki in order to benefit from the perks of each fighting style. This provides the power of Haki, while also giving attacks a natural debuff to Devil Fruit users.
Only Haki can transcend all! - Kaido
Still, though, it makes sense why there are so few Seastone weapons inOne Piece. These weapons are apparently hard to craft, break fairly quickly - as was shown when Smoker lost his Jitte on Punk Hazard - and do very little special that Haki can’t do. More often than not, inthe world ofOne Piece,the weapon a character uses rarely matters nearly as much as the person who is wielding it. Although there seems to be a small niche for this style of weaponry, the overall series ofOne Piecehas proven that Seastone weapons rarely provide any substantial benefit to combating Devil Fruit users.