Yami Yami no Mi

The Yami Yami no Mi, is a Logia type Devil Fruit that allows the user to become "darkness". "Yami" (闇) is the Japanese word for "darkness". In the Viz Manga, it is called the Dark-Dark Fruit. It originally belonged to Commander Thatch of Whitebeard's 4th division, but was stolen and eaten by Marshall D. Teach. This fruit is "unique" even for a Logia type.

Appearance
The Yami Yami no Mi is a purple fruit made up of many small teardrop shaped parts with swirl patterns, and spreading green leafage sprouting from the top. It closely resembles a pineapple or bunch of grapes in shape and appearance.

Strengths and Weaknesses
The first and foremost strength, as demonstrated by Blackbeard, is that it allows the user to control gravity. The gravity is visually demonstrated by a black smokelike liquid substance spreading out of the users body. As gravity sucks everything, including light, the fruit element is recognized as "darkness".

The darkness is a void that devours everything and crushes them. Due to this, the user can absorb physical matter and attacks of any type by sucking it into the darkness. The user can also use this ability to irresistibly pull the opponent to them, regardless in what state their in.

The most unique and powerful advantage of the fruit, is that the user also has the ability to nullify the powers of other Devil Fruit users by simply touching them and draining them of their abilities. All powers from other Devil Fruit types, be it Paramecia, Zoan, and Logia, are affected by this.

Similar to a black hole, the user can suck things inside a vortex. Although it seems that it does not completely compress that what is sucked as a black hole would do, rather it seems to be some form of space where things are stored. Blackbeard sucked an entire city to it, and eventually regurgitated everything back out reduced to scraps. The guards of Impel Down that Blackbeard sucked survived, although they were in shock.

The major weakness of this particular fruit, however, is that the darkness the user transforms into swallows up everything, including attacks. So unlike most Logia users, the user of the fruit is still vulnerable to attacks as they cannot turn into darkness in order to dodge them. If they fail to absorb the enemy's attack in time, the user can be hurt like any other normal human being or even more, as stated by Teach.

In addition, while the ability to nullify Devil Fruit abilities is powerful, the user must actually touch and remain in contact with the victim for the affects to remain constant, meaning that if the victim separates from the user's physical touch they quickly regain their Devil Fruit ability. Although, due to the fact that the user can control gravity, it is very difficult to avoid contact.

Other than that, the user is also affected by the standard Devil Fruit weaknesses.

Usage
The fruit's bestowed powers, as used by Teach, have been used so far for mostly combat purposes. He was able to defeat Ace in battle, his former commander, despite Ace possessing the Mera Mera no Mi.

The named techniques that are used by Teach that involve the Devil Fruit are as follows:


 * Black Hole (闇穴道 [ブラック･ホール], Yami Ana Michi [Burakku Hōru], literally translated as Black Hole Path): Blackbeard spreads his darkness over a large area and, much like a real black hole, swallows up anything he chooses. When swallowed it is subjected to a large amount of gravity and crushed, such as an entire village on the island of Banaro. During the Impel Down Arc, Teach has shown the ability to swallow up humans as well and crush them along with the debris. This was first seen being demonstrated before Ace.


 * Liberation (解放 [リベレイション], Kaihō [Ribereishun]): Used following Black Hole. Blackbeard expels all of the destroyed remains of what his darkness has swallowed up at once. This is especially good at demonstrating his power. This was first seen being demonstrated before Ace. Though it is unseen as of yet, in the anime Teach foreshadowed this attack can possibly be used to launch cannon balls and swords like projectiles.


 * Kurouzu (闇水, Dark Vortex): Extending one arm towards his opponent, Blackbeard activates the gravity power of his darkness to pull them into his grasp. Blackbeard can then attack them with his massive strength. This move is particularly useful in conjunction with the Yami Yami no Mi's power-nullifying abilities, since the target could easily avoid it by fighting at a distance from Blackbeard, as Ace attempted. The name of the attack is also a pun on the English word "closer", or "close". This was first seen being used on Ace in order to grab him.

Trivia

 * The Yami Yami no Mi is the is the only fruit shown in One Piece that has the power to nullify other devil fruit abilities.
 * This is the only logia-type Devil Fruit seen first as a fruit before it's shown what it does.