Dragon Slayer Magic

Dragon Slayer magic (滅竜魔法 Metsuryū Mahō) is a specialised form of magic which the series suggests can only be learned from the dragons themselves. Dragon Slayer allows the user, to a certain degree, transform their body into that of a Dragon. As a result of this, those with Dragon Slayer abilities are able to change their body to their own element, in both offensive and defensive styles. Because their own bodies can function as make-shift weapons unique only to themselves, Dragon Slayers are typically unarmed fighters who excel in physical combat and relying only with their magic. They can also consume external sources of their natural element to replenish themselves, although it has been demonstrated that certain foreign substances will substantially increase their power, i.e. Natsu's consumption of Etherion greatly increases both the strength of his body, and his magic. They are also naturally immune to the effects of their own element that came from both their own person and those from other sources, but must consume it through their mouths if they are to actually absorb it into their bodies. Dragon Slayers also have an incredible sense of smell too. There are "Old-style" Dragon slayers, the true practitioners, who learn from dragons and "New-Generation" Dragon Slayers, who implant Lacrima crystals into themselves, although it is only an imitation of the magic, according to Cobra, though this has yet to be proven true, as he may make this up to confuse and insult Natsu Dragneel.

Dragon Slayers are apparently quite rare; often, only a single one can be found within the membership of a single guild. Making the Fairy Tail Guild very unique as it has three on its roster

Apparently, Dragon Slayer Magic has limitless functions in Edolas, and is valued as a priceless resource for everyday uses.

"Why would a dragon teach another person how to beat dragons?"

- Lucy Heartfilia asks what we're all thinking, Chapter 1

Original Dragon Slayers
Dragon Slayers who have been raised by a dragon and taught their abilities.

Fire

 * Dragon: Igneel
 * Known User(s): Natsu Dragneel
 * Fire Dragon Slayer (火の滅竜魔法 Ka no Metsuryū Mahō): A Dragon Slayer ability which incorporates the element of fire into the user's body. This allows the user to produce flames from any part of their body, including their lungs, giving them the ability to, in essence, breathe fire.This also allows the user to consume external sources of fire to restore their body to a healthy state, meaning that they cannot use their own flames to renew themselves. 

'''As well as the added benefits of their elemental advantage, the Dragon Slayer magic gives the user a much greater level of endurance.This in turn is greatly enhanced by the consumption of Etherion, which not only boosts physical strength and magic, but also causes a layer of hardened scales to appear on the user's body. However, due to the fact Etherion has more elements than just fire fused into its sacred light, it is considered highly dangerous to take the substance into the body, regardless of the benefits, as eating any other element is essentially poison. '''

Basic Spells:  '**Fire Dragon's Roar (火竜の咆哮 Karyū no Hōkō''): Natsu breathes a long line of fire that becomes a large fireball that burns his opponent. Dragon Slayer's Secret Art (滅竜奥義 Metsu Ryū Ōgi): ''' '**Flame Lotus: Fire Dragon Fist (紅蓮火竜拳 Guren Karyū Ken''): Lighting his hands on fire, Natsu will rapidly punch his opponent. Each punch causes a fiery explosion. This attack was used to defeat Gajeel, the Dragon Slayer that uses Iron, and as an added result, had enough destructive power to destroy the entire guild building of Phantom Lord. In the anime it´s used to defeat Erigor in the Oracion seis arc. Unique Spells: '''
 * Fire Dragon's Claw (火竜の鉤爪 Karyū no Kagitsume): Natsu ignites his feet with a very large flame to increase the power of his kicks. He can also use the strong ensuing flames to jet-propel him in any direction he wishes.
 * Fire Dragon's Iron Fist (火竜の鉄拳 Karyū no Tekken): Natsu engulfs his fist in large flames and punches his opponent which makes his opponent fly away. Natsu renamed this ability Cat Fire (猫ファイアーNeko Faiā) while wearing cat mask.
 * Fire Dragon's Wing Attack (火竜の翼撃 Karyū no Yokugeki): Natsu takes hold of his opponent and ignites his arms and hands on fire in the form of dragon wings as support to throw them far away while burning them. In the anime, it has a different presentation. He jumps into the air, and then he ignites two streams of fire from his hands, then swings the streams of flames at his opponent, blowing them away.
 * Fire Dragon's Sword Horn(火竜の剣角 Karyū no Kenkaku): Natsu ignites his entire body on fire in order to ram into his opponent at full speed and then launches them high into the air with his large horn of fire.
 * Fire Dragon's Brilliant Flame (火竜の煌炎 Karyū no Kōen): Natsu creates a fire on both hands, and brings them together, creating a giant explosion that destroys everything around him. In the anime, he ignites both of his hands and combines the flame, but instead of creating a giant explosion, he throws a very large fireball at his enemy blowing them away.
 * Fire Dragon's Flame Elbow (火竜の炎肘 Karyū no Enchū): After Natsu ignites the tip of his elbow, he uses that flame to rocket and strengthen his fist into the opponent high in the air.
 * Fire Dragon's Crushing Fang (火竜の砕牙 Karyū no Saiga): With his hand ignited with a large flame, he gouges his hand into his enemy and quickly swipes his enemy away from his sight.
 * Flame Lotus: Exploding Flame Blade (紅蓮爆炎刃 Guren Bakuenjin): After a series of destructive attacks, Natsu finishes with a torrent of blade-shaped flames that strikes the enemy in a spiral formation. Every time the enemy is hit with a blade, it explodes and burns the enemy. Described as the ultimate Dragon Slayer technique, this attack is so powerful and destructive that it has been shown to smash through dragon scales which is known to have extremely tremendous endurance capabilities. This attack was used to defeat Laxus, the Dragon Slayer that uses Lighting, in chapter 126 and even caused Gildarts to take two steps back in chapter 206.
 * Hidden Fire Form; Flame Lotus: Phoenix Sword (紅蓮鳳凰劍 Shira-ni-gata: 'Guren Hōō Ken): Natsu ignites his entire body with the power of the Flame of Rebuke. He then charges towards the enemy and delivers a devastating punch he that blows up the enemy then proceeds to headbutt him. This is also described as The Ultimate Dragon Slayer Technique and the Dragon Slayer's Hidden Art, Sea Fire Style. This could be Natsu's strongest attack as not even Flame Lotus: Exploding Flame Blade was able to defeat Zero's strongest attack, though this may be because Exploding Flame Blade focuses on piercing penetration instead of mass destructive damage. This unstoppable and destructive attack was used to defeat Zero in chapter 161.

Iron

 * Dragon: Metalicana
 * Known User(s): Gajeel Redfox

Gajeel Redfox knows Dragon Slayer magic because he learned it from the dragon Metalicana. His Dragon Slayer magic deals with metal instead of such elements as wind and fire. Like Natsu eats fire to regain strength, he can eat his respective element to regain his strength. Gajeel's magic seems to deal with producing multi-sized iron rods as well as changing parts of his body into steel. Most of his attacks involve transforming his arm/s into hard-as-steel weapons, which he can do at will.

Spells:
 * Iron Dragon Scales
 * Iron Dragon Roar
 * Iron Dragon Club
 * Iron Dragon Blade
 * Iron Dragon Spear: Demon Firewood
 * Iron Dragon Hard Fist (Anime only)
 * Karma Demon: Iron God Sword

Sky

 * Dragon: Grandine
 * Known User(s): Wendy Marvell

Wendy is the Dragon Slayer of the Sky, which means that she uses old-style dragon slayer magic like Natsu and Gajeel. According to Charle, Wendy cannot use her magic in highly polluted areas. It is said that Sky Dragon Slayer magic actually focuses more on healing than damage which is impressive in its own right since true healing magic apparently has been lost. She has yet to be seen using this ability for the most part. As of now, Wendy has only shown support magic that boost her allies or her own physical abilities as well as basic first aid spells like detoxification. Her only known offensive spell is Sky Dragon Roar.

Spells:
 * Troia
 * Sky Dragon Roar
 * Vernier
 * Arms 

Frost
Adelheid is the Dragon Slayer of the Frost, and as such, she uses old-style dragon slayer magic like Wendy Marvell and Natsu Dragneel. Akthough her magic comprises around creating and controlling ice from frosted areas, or by freezing evaporated water, or normal water to create it. She can use the ice dragon's roar, and various other offensive techniuqes. It is shown however, that she can use Dragon Force willingly, although she rarely does it, as it takes quite a toll on her body, and she has a set time-limit for it's use.
 * Dragon: Unknown Ice dragon
 * Known User(s): Adelheid

Spells:
 * Ice Dragons roar
 * Ice Dragons Tail
 * Ice Dragons fist
 * Dragon Slayer Secret Art: Blizzard God's judgement

New-Generation (Artificial)
Dragon Slayers who have Dragon Lacrima implanted into their bodies. It is suggested that while they have vast power, they don't have the potential of true Dragon Slayers, as any Old Style has defeated a New Generation Dragon Slayer. However, it should be noted that it took both Gajeel and Natsu combined to take on Laxus, so that might have been more a show of Natsu's potential rather than the difference between New and Old generation itself.

Lightning

 * Known User(s): Laxus Dreyar

Technique(s):
 * Lightning Dragon Roar
 * Lightning Dragon Heavenward Halberd
 * Lightning Dragon Breakdown Fist (Anime only)

Poison

 * Known User(s): Cobra

Technique(s):
 * Poison Dragon Roar
 * Poison Dragon Twin Fang

Magma
Technique(s):
 * Known User(s): Franz Kainu
 * Magma Dragon Fist
 * Dai Funka
 * Ryusei Kazan
 * Gansho Kenga

Dragon Force
Dragon Force is when a powerful Dragon Slayer starts to turn their own body into a humanoid dragon. Dragon Force gives the user a huge power up and almost makes the user unbeatable. According to Zero, it is the most powerful and final state a Dragon Slayer can attain. It increases the damage from standard Dragon Slayer attacks. It causes their body to cover in scales and their magic aura to become visible, taking the shape of a dragon. For Old-Style Dragon Slayers, certain conditions must be met in order to achive Dragon Force state; the only one known so far would be to eat substances with powerful magical properties, preferrably those related somehow to the element they can control and consume. Natsu (through consumption of Etherion and from the Flame of Rebuke), is one of the three True Dragon Slayers to activate this power. It is likely, given the description as the final state a dragon slayer can attain, that a dragon slayer may eventualy gain access to it without outside sources of power.

Trivia

 * Franz Kainu is the only known Dragon Slayer, new or old, who does not use the word dragon in his attacks.