Igneel

Igneel (イグニール Igunīru) is a Dragon known as The Fire Dragon and The Flame Dragon King, and is the foster father of Natsu Dragneel.

Appearance
Igneel is a gigantic Dragon whose bodily majority is covered with dark, red scales. Igneel's lower body, specifically his belly, the inner portions of his long tail, and legs, is beige in color. Igneel also has noticeable scars on his belly and neck, with the largest one, which is X-shaped, located around the center of his body. His back has numerous black spikes, reaching down from the back to the end of his tail. Igneel has a triangular head with horns, a pair of large, round eyes with yellow sclera (which are usually seen as glowing, obscuring his dark, round pupils) and a sharp horn pointing upwards just above his nose. Igneel also sports very sharp canine teeth, and has claws with long, sharp, red nails. Igneel's large bony wings resemble a bat's, with rippled tips. Additionally, Igneel has four hind legs.

Personality
Igneel has been shown to be a loving father figure towards Natsu, before his untimely departure. Despite leaving Natsu, Igneel, however, is shown to be incredibly protective of Natsu, and watches him from afar. Contrary to his quite often portrayed loving personality, Igneel can also be rash, angry and violent when he feels the situation calls for it. He has also shown a high degree of arrogance, referring to himself as "the one and only Igneel" during Grandeeney's visit.

According to Grandeeney, like Natsu, Igneel has a tendency to take things to the excess.

History
Igneel, also known as the Flame Dragon King, dueled with his close friend Atlas Flame several times, usually arising atop and consuming the flame clad Dragon's flames. Four hundred years ago, Igneel failed to destroy the most vile Demon in the Books of Zeref: E.N.D. Many years later, Igneel taught a young human boy, Natsu Dragneel, how to write, speak and use his signature Lost Dragon Slayer Magic: Fire Dragon Slayer Magic, which gave Natsu the traits of Igneel himself. For unknown reasons, Igneel, alongside every other Dragon, disappeared on July 7th, X777 without so much as a goodbye, leaving Natsu to fend for himself.

Tower of Heaven arc
Note: Events take place in the Tower of Heaven arc in the manga, but Fighting Festival arc in the anime. After the events that transpired at the Tower of Heaven, Igneel is seen residing in a volcanic region, talking to the Dragon who raised Wendy Marvell, Grandeeney, about Natsu. Igneel immediately orders Grandeeney to leave, while she warns him that if Natsu continues fighting as recklessly as he has, he may wind up dead. Igneel then makes a reference to the Black Wizard, Zeref, and the Dragons' removal from human affairs. He then shows that he is in fact very firm about leaving humans alone, especially Natsu. Hearing these words, Grandeeney leaves, hoping that Natsu's friendship with Wendy will be better than his "friendship" with Metalicana's foster son, Gajeel Redfox.

Oración Seis arc
Note: This event only occurs in the anime and does constitute as canon material. During Natsu's fight against Zero, Natsu is sent to the 'Land of Nil' through Zero's Magic Genesis Zero, and opening the 'Gate of Wraithwail'. Through there, Natsu is about to lose hope, cursing everything he had done. Suddenly, he hears Igneel's voice, saying that Natsu should not be defeated by the likes of Zero. Igneel also mentions that this is what a child of Igneel is and a flashback focuses on Natsu questioning Igneel on how he's supposed to destroy a mountainous rock. Igneel explains to him that he must not let his feelings get the better of him, saying he must not lose faith in his power. He encourages Natsu, saying he's a Dragon Slayer and that he must not forget the pride that comes with that title. Igneel concludes by stating that he is with Natsu, and, with this, Natsu manages to burn off Zero's Magic and come back from the Land of Nil.

Grand Magic Games arc
Igneel is seen talking to himself about the potential of the Dragon Slayers Weisslogia and Skiadrum created. He then wonders if humans will ever surpass Dragons, or if it is merely a dream. Igneel then notes that the time for the Dragons to take action has come, as the Dragon King Festival draws ever near.

Tartarus arc
While Acnologia springs into action, arriving at the Tartarus' location, Igneel wonders if "the time has come". Talking to Natsu whose body reacts to Acnologia, Igneel expresses his belief that Natsu is capable of E.N.D.'s defeat. While Natsu is confused, not knowing why he can hear the Fire Dragon, Igneel states that he has to deal with Acnologia. Revealing that he has been inside Natsu's body this whole time, Igneel asks for forgiveness and tells his son to live as he charges the Black Dragon. Igneel clashes with Acnologia mid-air and the two begin to fight over the Tartarus ruins, though are interrupted when Natsu launches himself at Igneel, demanding that the Dragon explain why he disappeared so many years ago. Angered, Igneel tells Natsu to stay away, and uses a large attack on Acnologia to blast the other Dragon back, almost accidentally shaking Natsu off in the process. Grabbing the Dragon Slayer in his claws, Igneel tells Natsu to leave as Acnologia regains his composure after the attack, and, recalling that Natsu works in a guild, asks the Mage to complete a job for him. Igneel then points out Mard Geer in the ruins below, and tells Natsu to go retrieve the book of E.N.D. that he holds. Natsu questions why such a thing is important, though Igneel merely remarks that the book should not be in Mard's hands, and warns Natsu to never open it; he also agrees that the reward for Natsu's completion of the job request will be an explanation of anything Natsu wishes to know. With Natsu agreeing to take on the job, Igneel tosses the Dragon Slayer down to Mard, before he turns to continue his fight against Acnologia.

Magic & Abilities
Telepathy (念話, テレパシー, Terepashī): Igneel is able to make use of this form of Magic, allowing him to communicate with Natsu telepathically.

Dragon's Roar: Similar to other Dragons and Dragon Slayers, Igneel has shown the ability to use his element in the form of an attack coming from his mouth. In Igneel's case, the attack takes form of a large-scale destructive fire breath attack, similar to Natsu's Fire Dragon's Roar and Atlas Flame's, capable of completely destroying the surrounding area in a massive explosion.

Flight: Being a Dragon, Igneel possesses the ability to fly through the air using his wings.

Fairy Tail Portable Guild 2
Igneel appears as one of the two major bosses of the PSP game Fairy Tail Portable Guild 2, being the strongest of the bosses.

Fairy Tail: Zeref's Awakening
Igneel makes a second appearance in the sequel, Fairy Tail: Zeref's Awakening, as the strongest boss of the game.

Quotes

 * (To Grandeeney) "Leave this place! Do not interfere with the humans!!!"
 * (To Grandeeney) "Do you mean to anger the one and only Igneel?!"
 * (To Natsu Dragneel) "I, Igneel, am with you!"
 * (To himself about the Dragon Slayers) "Can humans exceed Dragons or is it just an empty dream..."