Dragon

Dragons (ドラゴン Doragon) are one of the most powerful and prominent creatures in High School DxD.

Summary
Dragons are beings created from large masses of energy and act freely and selfishly. Despite this, Dragons have an extremely high level of intelligence.

Dragons are creatures that represent power. As such, in all ages, Dragons are admired, respected, and feared by all. The Dragons are the only creatures whom, as a race, did not side with any of the three factions in the Great War, unlike the Youkai, European Monsters, spirits, fairies, and other supernatural races. However, some individual Dragons "did" join one of the Three Factions.

Unlike other races that have long lifespans, all Dragons have a limitless lifespan, as they do not age after reaching maturity and will only die if they are killed.

Currently, almost all of the Dragons of legend are sealed in Sacred Gears, dormant, missing, or dead.

Appearance
Dragons are creatures with reptilian traits. There are two physical types of Dragons, Western Dragons and Eastern Dragons.


 * The Western Dragons are lizard-like creature that stands on four legs, leathery or bat-like wings growing from their backs, and a long, muscular tail.


 * The Eastern Dragons are typically portrayed as serpentine creature that have long, slim bodies with four legs, and without wings.

Various Dragons come in different colors, from red (Flame Dragon and Ddraig) to white (Albion) to blue (Tiamat and Sprite Dragon).

Classes
The Dragons are divided into many different classes. There are the normal Dragons, the Dragon Kings which are above the normal Dragons, the Heavenly Dragons which are above the Dragon Kings, and the True Dragon and Dragon God, the highest class of Dragons.

True Dragon
The True Dragon (真龍 Shinryū) is a class that solely belongs to Great Red, the Apocalypse Dragon and the True Red Dragon God Emperor who is known as the "Dragon of Dragons (D×D)". It is the title given to Great Red as the most powerful of Dragons. Great Red is the only Dragon that belongs to this sub-class. However, in Volume 12, it is said that Issei could be thought of as a small True Dragon because of having his new body made from Great Red's flesh.

Dragon God
The Dragon God (龍神 Ryūshin) is a class that solely belongs to Ophis, the Ouroboros Dragon and founder of the Khaos Brigade.

Two Heavenly Dragons
The Two Heavenly Dragons (二天龍 Nitenryū) are Dragons with powers that rival that of a God and Satan and are considered to be of the highest class of Dragons. The two Heavenly Dragons are the Red Dragon Emperor, Ddraig, and the White Dragon Emperor, Albion.

In the past, the two Heavenly Dragons fought a fierce battle, which was interrupted by the Angels, Devils, and Fallen Angels who are at war during the time. In anger, both Dragons attacked the leaders of the Three Factions, which led to their bodies being destroyed and their souls being sealed into two separate Sacred Gears.

Currently, both of the Heavenly Dragons are sealed inside two separate Sacred Gears: Boosted Gear and Divine Dividing.

Five Great Dragon Kings
The Five Great Dragon Kings (五大龍王 Godai Ryūō) are a group of five (previously six) unique Dragons with high destructive powers, rivaling those of Ultimate-Class Devils or even the Four Great Satans. The Five Dragon Kings are Tiamat, Yu-Long, Vritra, Midgardsormr, and Fafnir. Tannin was also one of the Dragon Kings before leaving and joining the Devils.

It is unknown how a Dragon reaches this class, as the other classes appear based on the Dragon's specific type, while the Dragon Kings are of different types and factions.

High-level Dragons
High-level Dragons: A Dragon class that belongs to normal Dragons. There are three Dragons within this class: the Sprite Dragon, Flame Dragon, and the Blizzard Dragon. All three have appeared within the series.

Low-level Dragons
Low-level Dragons: A Dragon class that belongs to normal Dragons. The only Dragon that has been revealed and belongs to this class is the Earth Dragon.

Evil Dragons
Another class of Dragon that is first introduced in Volume 14. The Evil Dragons (邪龍 Jaryū) are known to be more powerful than the Five Dragon Kings while the most powerful Evil Dragon in existence, Crom Cruach, is said to be as strong as a Heavenly Dragon. The Evil Dragons are stated to be the most vicious and brutal of all Dragons, all being dangerous battle maniacs that want to destroy everything including themselves. They are considered as "broken Dragons".

The Dragons of this class include:


 * Crom Cruach


 * Aži Dahāka


 * Apophis


 * Grendel


 * Yamata no Orochi


 * Ladon


 * Níðhǫggr

Technically, Vritra is considered to be in this category as well, but he pales in comparison to their iniquity. Among the Evil Dragons, the ones that were the most brutal and stood at the top were:


 * "Crescent Circle Dragon" Crom Cruach


 * "Diabolism Thousand Dragon" Aži Dahāka


 * "Eclipse Dragon" Apophis

Currently only Grendel and Crom Cruach has appeared in the series while Aži Dahāka has been mentioned to be alive, but has yet to appear. In Volume 16, Rizevim reveals that with the help of the Sephiroth Graal, he could mass-produced Evil Dragons, using it on the Vampires that modify themselves using the Sephiroth Graal. The mass-produced Evil Dragons are said to have at least the strength above a Mid-class Devil.

Other Dragons
There are several Dragons that do not have proper classes due to being a former Dragon or a Dragon that has been forbidden. The two Dragons that belongs to this category are Tannin (former Dragon King) and Samael (a Fallen Angel that was turned into a Dragon and sealed). Issei Hyoudou, a humanoid Dragon, could also be considered as a Dragon of this class, as his body is made from the Great Red's flesh through Ophis' powers. This, along with the Boosted Gear, places Issei as a Dragon under the Dragon God, True Dragon, and Heavenly Dragon classes but at the same time he is not.

Powers and Abilities
The abilities of a Dragon differ between classes, their specific races, and in some cases, the specific Dragon. All of them have demonstrated the power of flight and their own elemental breath weapon (either fire, ice, or lightning).

A frequently seen trait amongst the higher classes of Dragons is the ability to change their appearance to varying degrees. This trait ranges from changing their size (Tannin) to completely changing their outward appearance (Yu-long, Crom Cruach, and Ophis).

It has been stated (and shown by Issei) that Dragons draw strong allies and enemies to them.

Dragon Gate
The Dragon Gate is a magic circle exclusive to the Dragons. The Dragon Gate allows them to summon another Dragon. While the Dragon Gate insignia can be drawn by someone else, it will only respond when there is a Dragon nearby.

The Dragon Gate insignia is positioned after the Five Dragon Kings, Tannin, and the Two Heavenly Dragons. Each of which is represented on the magic circle by a different color:
 * Ddraig - Red
 * Albion - White
 * Tannin - Purple
 * Tiamat - Blue
 * Yu-Long - Green
 * Vritra - Black
 * Midgardsormr - Grey
 * Fafnir - Gold
 * Grendel - Dark Green

Despite so, there appears to be other methods to use the Dragon Gate; in Volume 9, the Hero Faction intended to use a brainwashed Yasaka and the spiritual energy from Kyoto to replace the use of the Dragons to open the Dragon Gate.

Trivia

 * There is a race of Dragons who require a special fruit, called the Dragon Apple, to survive. All the Dragon Apples on Earth have been destroyed due to climate changes, with the ones growing in the Underworld all existing within Tannin's territory.
 * The Dragon Apple was the main reason for Tannin to become a Devil.
 * The Dragons have a disease called the Dragon Flu.
 * Dragon Flu can also be caught by the users of Dragon-type Sacred Gears.
 * Male Dragons take likings to females of other races, while hating other males.
 * This is in fact the reason why Rassei attacked both Issei and Kiba.
 * Before the introduction of Ophis, the Heavenly Dragons were stated to be the highest class of Dragon.
 * Both sub-species Balance Breakers of Blade Blacksmith are Dragon related.