Gura Gura no Mi

The Gura Gura no Mi is a Paramecia type Devil Fruit that turns the user into a "Quake Man," allowing the user to create shock waves (or "quakes"). "Gura Gura" comes from a Japanese onomatopoeia which means unstable or shaking. It was eaten by Edward Newgate, and later stolen through unknown means by Marshall D. Teach following the death of the former. This fruit is fearsomely reputed to be able to destroy the world, and is considered to be the strongest Devil Fruit within the Paramecia-class, having powers no weaker than that of a Logia. In the Viz Manga and FUNimation subs, it is called the Tremor-Tremor Fruit.

Strengths and Weaknesses
It may very well be us that meet our end here today... Because that man... HOLDS THE POWER TO DESTROY THE VERY WORLD!!!

This fruit's major strength is that it allows the user to generate massive shock waves, which can travel in the ground, the seafloor, or even in the air.

Because of this, Fleet Admiral Sengoku has stated that Whitebeard holds the power to destroy the world. However, though incredibly powerful, this almost seemed to be an exaggerated description. The fruit can take down an entire island with ease, although its limitations are noticeable: it took several shots to take down the Marine Headquarters base (in fact, Whitebeard failed to do so before dying, and Blackbeard almost completed the task); the shock waves were blocked by the siege wall {albeit it was made from an especially strong metal superior to ordinary steel); Admiral Aokiji was capable of stopping the tsunami. Although to note the situations at hand, it was only until after Ace's death that Whitebeard truly attempted to take down Marineford in his anger, but it was Teach who truly was willing to destroy the island using both his Devil Fruit powers. And although neither men succeeded in taking the island down (having both been stopped and the latter lacking control of the power yet), the aftershocks and tsunami were felt outside of the island. Sengoku's claim may have referred to the aftereffects of the fruit however, as they may indeed have "the power to destroy the world".

When Blackbeard took this Devil Fruit's power through an unknown method, he claimed that with this power of earthquake which "brings destruction to all", combined with the darkness that "reduces anything to nothingness", he is truly invincible and the strongest.

This Devil Fruit's powers are most noted to be a hazard to both friend and foe alike, as noted by both the Whitebeard and Blackbeard Pirates. This is largely because although the user seems to be able to control the magnitude of the shock and its point of impact, the quakes produced by the fruit themselves shake the area they hit indiscriminately. Because of this, allies of the user have to be prepared for the impacts unless they want to become unintended victims of them.

This Devil Fruit has no apparent weakness, aside from the standard Devil Fruit weakness. However, the three Admirals have been able to stop Whitebeard's shock waves from affecting Marineford's execution platform, possibly using a strong Busōshoku Haki together. Also, the Siege Wall that Sengoku planted was composed of material that even Whitebeard's shock waves could not shatter.

Usage
Whitebeard has so far demonstrated three separate, distinct skills with his Devil Fruit. Blackbeard was also capable of using all of them, but he still lacks the mastery of the Fruit his former captain had.

Trivia

 * This is the first Devil Fruit to be shown to belong to two separate users, having been acquired by Blackbeard after the death of Whitebeard, via an as-of-yet undisclosed method. Furthermore, it now shares a distinction with the Yami Yami no Mi as the first two fruits to be wielded concurrently by the same user.
 * This Devil Fruit's name is reminiscent of Whitebeard's laughter style, "Gurarara". This attribute is shared with Perona's Horo Horo no Mi.
 * The Gura Gura no Mi's powers is one of the three aspects that made Whitebeard resemble the Greek God Poseidon (the other two being his polearm and his status as a Yonkou), as the Emperor of the Seas who could cause earthquakes and tsunamis.
 * Unlike most characters in the series, Whitebeard has not named any of the attacks he has used, a distinction he shares with the Juracule Mihawk and Gin, above some other serious characters.