Fafnir

Fafnir is one of the Five Great Dragon Kings. He is the Golden Dragon known as the Gigantis Dragon.

Appearance
Having at least lived for 10,000 years, Fafnir is a golden Western Dragon that is more than 10 meters tall, who lacks a pair of wings that grow on his back unlike the usual Western Dragon, and has a horn on the tip of his nose. In his first appearance, Fafnir had a pair of Asia's panties on his horn. In Outrage mode, Fafnir is able to manifest a pair of wings.

Personality
Little is known of Fafnir's personality due to him being sealed in Azazel's Artificial Sacred Gear, as well as the fact that there are very few instances of him being described. He's not as proud as other dragons. As mentioned by Sona, Fafnir has a tendency to collect treasures throughout the world.

In his first appearance, Fafnir is revealed to be a perverted Dragon with a fetish for panties, sniffing them and referring to them as "treasures". According to Ddraig and Albion, Fafnir wasn't as perverted in the past as he is right now.

History
Not much is known about Fafnir except that he was previously killed by the original Siegfried who wielded the Demon Sword Gram but was later revived by the Norse Gods. Azazel also believes that the influence of Odin in his revival is the reason for the dragon king's perverseness. Prior to the series, he made a contract with Azazel to aide him in his Sacred Gear research by allowing himself to be sealed inside Azazel's Artificial Sacred Gear.

Birth of the Breast Dragon Emperor
In Volume 4, Azazel reveals that he made a pact with Fafnir to be sealed inside his Artificial Sacred Gear, the "Down Fall Dragon Spear".

The Heroic Oppai Dragon
In Volume 10, Ddraig privately contacted Azazel through Fafnir's jewel to ask him to search for a Dragon Counsellor as he has been crying unconsciously.

The Legend of Oppai Dragon and his Lively Companions
It was revealed in Volume 14 that he had made a pact with Asia after being freed of his contract with Azazel. He helped awaken Ddraig from his slumber with the help of Vritra during the battle between Khaos Brigade and the members of the Occult Research Club and the Student Council.

In Volume 15, he is shown to be in the indoor pool of the Hyoudou Residence while having both Ophis and Rassei seated on his head. After standing in the pool next to Asia he commented on wanting to drink the pool water she had been in after he saw her in her swimsuit.

In Volume 16, Fafnir participated in the battle against Crom Cruach, but demanded Asia's school swimsuit first as payment for their pact. He provided the replica of the magical bullet, Tathlum, that Azazel gave to him as payment for their previous pact to be used against Crom Cruach.

Fafnir, together with Vritra, was asked by Ddraig and Albion in Volume 17 for help to convince the past possessors of Divine Dividing into helping them. It was later revealed that they were able to convince the past possessors and it was Fafnir who greatly contributed in the cause by introducing the wonders of panties to the past possessors.

After being summoned by Asia to help them in the battle against the mass-produced Evil Dragon, Fafnir appeared wearing a chef's hat with equipments and props used in a cooking show. He then cooked an original recipe of his, "Diavola Asia-tan Fried Panty" and was able to captivate the hearts of the mass-produced Evil Dragons with some of them even crying.

In Volume 18, Fafnir was summoned by Asia to help defend heaven. He took a brutal beating from Rizevim Livan Lucifer, but went into Outrage mode after seeing Rizevim slap Asia, knocking Lilith aside and biting one of Rizevim's arms. Issei then took over the fight. Afterwards, Fafnir lost consciousness, going into a deep hibernation of sorts until his injuries had healed.

In Volume 20, it was revealed that after his fight with Rizevim in Volume 18, Fafnir converted his spirit into a curse that allowed him to endlessly attack the Super Devil in his dreams, chasing Rizevim relentlessly and killing him again and again. Then, just before Vali was about to deliver the killing strike, Fafnir appeared and bit Rizevim in half with his mouth, killing him.

Powers & Abilities
Immense Strength: As one of the Five Great Dragon Kings, Fafnir is very powerful. He is powerful enough to knock down Lilith easily and overpower Rizevim Lucifer who is a Super Devil. By entering the Outrage state he can easily overpower Rizevim alone with just brute force.

Golden Aura: In his first shown battle, Fafnir released a golden block of aura from his mouth that extinguished Grendel’s flame, showing the ability to negate the power of his enemies. The Golden Aura can also be used to help store treasures that is given or collected by Fafnir and can be use as a powerful golden barrier. It can be useful to enhanced Asia`s Twilight Saint Healing for healing abilities and to negates all attacks of an opponents.

Telepathy: Fafnir can telepathically talk to peoples and dragons,especially to Asia in her mind and dreams.

Enhanced Speed: Fafnir is very fast despite of his large body that he can keep up with Rizevim Lucifer who is a fast Devil. He is fast enough to create an afterimage of him, as shown in his battle against Rizevim where use his afterimage to distract his attention, allowing Fafnir to sneak at Rizevim's back and bit off his left arm.

Immense Endurance: He can endure powerful blows like he did to protect Asia in the battle in Heaven against Rizevim. Despite spiting blood to his body he can endure it without any problem.

Treasure Summoning: In his battle with Rizevim Livan Lucifer, Fafnir displayed the ability to summon his treasure trove of legendary weapons and also use their abilities. He summons them from his mouth,this weapons are said to be rare and high class that can kill a High Class Devil and can injure an Ultimate Class Devil or possibly a Super Devil like Rizevim.

Outrage: Fafnir, when angered, can enter into a state that immensely increases his power. He can grow a pair of wings in this state. In this state he is able to overpower Rizevim Lucifer who is a Super Devil by tearing off his right arm. Also, he was also seen to be able to kill Rizevim Lucifer, a Super Devil, with a single bite.

Dragon Flames: As a dragon, Fafnir can incinerate and create a powerful dragon flames and fire balls. As shown when he use it against Rizevim.

Magic: Fafnir was also shown expertise of using magics and forbidden spells like Azi Dahaka. As it seen when he opens the Dragon Gate on his own to kill Rizevim because of his deep hatred towards the super devil.

Curse: Fafnir is able to turn his spirit into a powerful curse that allows him to attack his enemy in their dreams eternally that can make them go insane and die.

Flight: Though he is originally a flightless dragon, by manifesting his powers and entering his Outrage mode he can somehow manifest his wings in order to fly.

Trivia

 * Fafnir's title Golden Dragon Monarch (黄金龍君) is loosely based from the name of the Pokemon Suicune.
 * According to Fafnir, Asia's panties taste like peach.