Tetsu Tetsu no Mi

Tetsu Tetsu no Mi (鐵鐵の実 Iron Iron Fruit) is a Logia-type Devil Fruit that allows the user to change parts of there body (or the entirety of it) into Iron, making the user into an Iron Human (鉄の人間 Tetsuno Ningen). It enables the user to be able shape the Iron in a number of forms for different purposes. It was eaten by Gajeel.

Strengths and Weaknesses
The fruits major strength is its ability to turn its user's body into iron, whether it be a limb or an entire body. This fruit is one of the few Logia where the consumer can be hit with a physical attack, because iron is a solid-state element, and thus the user cannot simply dissolve out of harm's way as most Logia-users can. Although, most attacks are still ineffective against this fruit because the Iron defense renders most attacks useless. However, after the four year time-skip, Gajeel discovers the ability to transform his body into Iron Sand, making physical attacks completely useless against him.

The Iron is also completely resistant to any other known forms of metal, and minerals due to it's incredible hardness. It's hardness creates an offense that is able to easily shatter the hardest of minerals with ease. Despite it's incredible defensive ability, it is not so resistant to other Devil Fruit powers, as it can be damaged by powerful attacks, even leaving cracks in the iron.

It was later discovered by Gajeel through intense training and battle that the Fruit also gives the user the ability to control magnetism. This allows Gajeel to control and shape any metals within a given area and use them at will, including the ability to merge them with himself. This advanced ability also allows the user to convert objects into iron by increasing the iron content within the object on a molecular level until it is usable. After mastering the use of Iron Sand, Gajeel is able to create metal objects and weapons separate from his own body by molding Iron Sand.

Using the same premises for the Iron Sand, Gajeel discovered he could also control the Iron in his own blood. Able to manipulate his own blood at will, Gajeel was able to use the Chitetsu form.

One major weakness of the fruit comes from it's ability to transform the user's body into Iron. While using the fruit, a user's body maintains the properties of Iron, meaning user is very susceptible to low temperatures and are conductible to both electricity and heat.

Usage
The utilization of this fruit revolves around the use of iron for both offense and defense, with the user being capable of creating a wide array of weapons from their body to attack the opponents both in melee and from a distance, and to cover their body with iron in order to dramatically increase their defensive power, at the same time greatly boosting their offense as well. The metal produced by this fruit is stronger than normal iron, and capable of rendering some physical assaults useless

Techniques
Gajeel an advanced set of techniques revolving around the Fruits ability to manipulate Magnetism.
 * Tetsuroa (鉄ロア Tetsu Roa, literally meaning "Iron Roar"): After gathering Iron podwer into his mouth, Gajeel shapes it into a powerful tornado which he subsequently emits and sends towards his foes. Such tornado possesses immense force, being capable of generating powerful explosions and inflicting heavy blunt damage, but also releases sharp shards of metal in the process, to shred the opponents' body.
 * Tetsuken (鉄 剣 Tetsu Ken, literally meaning "Iron Sword"): Similar to Tetsubou, but possessing cutting instead of blunt power and thus being possibly deadlier, Gajeel transforms his arm or leg into a large, jagged steel blade. The spikes along the blade's edge make its slashes more painful and dangerous, and the weapon's length can be increased to reach enemies away from him. The sword can also function like a chainsaw, effectively increasing its damage.
 * Tetsuken - Kisshin (鉄 剣 - 鬼薪 Tetsu Ken - Kisshin, literally meaning "Iron Sword - Demon Logs"): The user turns their arm into a sharp spearhead,, from which a large number of steel spears is fired towards his enemy multiple times in rapid succession.
 * Tetsujinken (鉄神剣 Tetsu Jin Ken, literally meaning "Iron God Sword"): The user claps their hands together, combining the iron from both arms to create a gigantic iron sword. The user then proceeds to slash the sword, destroying a substantially large area in front of them.
 * Tetsubou (鉄 棒 Tetsu Bou, literally meaning "Iron Rod"): Gajeel transforms his arm or leg into a large steel club, increasing his punching and kicking power.  The clubs can be elongated at Gajeel's will, making them powerful ranged weapons. Also, for added maneuverability and to take opponents off-guard, the club can be rapidly turned into the similar Tetsuken.
 * Tetsubou - Madara (鉄 棒 - 斑 Tetsu Bou - Madara, literally meaning "Iron Rod - Spots"): While using Testusbou, the user can create multiple smaller clubs to grow and elongate the original, hitting many enemies at once.
 * Tetsuroko (鉄 鱗 Tetsu Uroko, literally meaning "Iron Scales"): Gajeel transforms part of his body (or the entirety of it) into iron that bears the appearance of steel scales to dramatically increase his offense and defense. When punching and kicking while covered by these scales, Gajeel is capable of creating powerful gusts of wind through mere kinetic force, as proof of his improved strength. These scales are strong enough to shatter bone and solid stone alike, resilient against flames and other irregular attacks, and much harder than normal iron.Tetsuroko.png
 * Tetsuroko Gō Ken (鉄鋼拳 Tetsu Uroko Gō Ken, literally meaning "Iron Hard Fist"): The user punches their target while covered in Tetsuroko, greatly enhancing their punching power.
 * Tetsuroko Gō Kikku (鉄鋼キック Tetsu Uroko Gō Kikku, literally meaning "Iron Hard Kick"):The user kicks, using the extreme force of the iron scales to enforce the power of the move and release an air pressure wave from the attack, capable of destroying the ground beneath the air vacuum.
 * Satetsu (砂鉄 Satetsu, literally meaning "Iron Sand"): Gajeel places his palm on top of an object or area, and releases thousands of micro-iron filaments that fuse with Gajeel's targeted area, creating a green flash that signifies the target being transformed into Iron. After creating an Iron Base, Gajeel breaks it down into Iron powder he nicknames Iron Sand. This power is manipulated by Magnetism, and can be formed into giant static shapes or used in a mass of Iron Sand. Blood_Steel.png
 * Chitetsu (血鉄 Chitetsu, literally meaning "Iron Blood"): By discovering the ability to manipulate Iron on a molecular level, Gajeel discovered the Iron Iron Fruit's ability to manipulate the iron in blood. By manipulating the iron is his own Blood, Gajeel can freely use the blood from wounds as a sharp liquid that can cut through the toughest metal. Gajeel refers to the usage of his own blood as annoying and cowardly, and prefers not to use it.
 * Tetsu Buso (鉄武装 Tetsu Busō, literally meaning Iron Armament): Gajeel mastered Bosushoku Haki by training in Skypiea with Luna. He imbues his body with Busoshoku Haki while already under the effects of his Tetsuroko technique, giving his iron body a dark and shiny appearance. By combining his iron defense with Busoshoku Haki, Gajeel is effectively squaring his defensive ability. He first used this technique to defeat Vilan of the White Wing Pirates. Before activating this ability, Vilan was able to easily cut through Gajeel's iron body with her vectors. After it's activation, she was unable to deal Gajeel any damage at all.

Post Time-skip Techniques
After mastering the use of Iron Sand, Gajeel is able to mold Iron Sand into metal objects at will, adding a whole new dynamic to Gajeel's offensive techniques.
 * Tetsuara (鉄あられ Tetsu Ara, literally meaning "Iron Hail"): A gunshot-like attack which uses Iron Sand hardened into minuscule grains to attack simultaneously across a vast range. The bullets are so fast that they are difficult to see. The moment the user has finished preparing the attack, evading it becomes extremely difficult. Using the repellent force of magnetism, the speed of the bullets is rapidly increased after they are shot. Furthermore, the user can also use an attack pattern where the Iron Sand bullets are shaped into sharp needles, increasing their ability to wound or kill the opponent.