Crom Cruach

Crom Cruach is an Evil Dragon known as the Crescent Circle Dragon and is said to be the strongest Evil Dragon. He was formerly affiliated with the Khaos Brigade's Qlippoth along with the other Evil Dragons.

Appearance
He has the ability to shapeshift into a human form or a Dragon form. In his human form, Crom Cruach has the appearance of a tall man wearing a black coat with a mixture of black and blond hairs as well as heterochromatic eyes where his right eye is gold and his left eye is black.

In his true form, Crom Cruach resembles a majestic jet black Dragon with a black and golden aura surrounding him. Since he has black wings, Crom Cruach is a Western Dragon.

Personality
Unlike the other Evil Dragons, Crom Cruach appears to be calm and quiet as he usually leans on nearby walls when on standby. He also appears to put his objectives first as, despite his love for battles, he was willing to leave after ten minutes when he was only told to hold off his enemies. He also seems to have a much greater amount of self-control since he backed down after Issei refused to fight due to exhaustion.

As noted by Vali, Crom Cruach is even more of a battle maniac than he is and spent all the years he was absent training between the human world and the Underworld. When fighting, Crom Cruach prefers to fight alone, getting angry if an outside combatant interferes with his battle. He has also a very strange demeanor, such as not repeating his words more than twice as is seen when Issei asked him in Volume 20, and also tends to not answer a direct question or order if he deems it to not matter, and will answer in a silent response.

Crom Cruach also has an extremely merciless side which is what earned him an infamous reputation as an Evil Dragon as shown when he ruthlessly brutalized Niðhoggr after the latter attacked Ophis.

Despite all of this traits, he has a great deal of honorable and respectful nature of a true Dragon, even though an Evil Dragon just like Apophis and Azi Dahaka since he also hates dirty and nasty tactics and tricks, as he states, during his intervention against Niðhöggr through the DxD Gremory group, that he will relentlessly and ruthlessly beat him up until his consciousness fades. Tannin also noted that out of all the Evil Dragons, he is the purest one despite being called the most evil out of all of them, because he lived for many centuries and Crom Cruach's eyes have seen many things including the vast changes in the history of the Human world which, in turn, have changed Crom Cruach's views.

History
In the past, Crom Cruach was controlled by Balor, the Evil God from the Irish Mythology. After Balor was defeated by Lugh, Crom Cruach went around to observe the human world and the Underworld as part of his training and experience. Afterward, he left the land where he resides due to finding the intrusion of Christianity an annoyance.

Sometime during his training, he met and joined Rizevim Livan Lucifer's group in order for him to be able to fight strong foes and see the place where Dragons would reach at the end.

The Legend of Oppai Dragon and his Lively Companions
Crom Cruach first appeared in Volume 16 where he was introduced by Marius Tepes as their bodyguard. When the extraction of the Holy Grail started, he commandeered Grendel's fight and fought against Issei with his True Queen and Vali with his normal Balance Breaker and was able to successfully stall them for 10 minutes without taking any major damage.

In Volume 18, Crom Cruach took part in the invasion of Heaven. Unlike Walburga and Ladon, he only fought casually, only doing enough to fulfill his role. It was only when he fought against Issei while he was in True Queen mode that he became interested. He was winning the fight, but Walburga entered the fray. The two argued and Crom Cruach lost the will to continue the fight. He walked away, telling Walburga that she was on her own. He was then challenged to a fight by Dulio Gesualdo, which he happily accepted. He later arrived at the site of Issei's battle with Rizevim Livan Lucifer alongside Dulio Gesualdo. When Rizevim called for him to retreat with him, he wordlessly refused. Right before leaving Heaven, he questioned Issei about whether is he a Devil or a Dragon, challenging Issei to another fight in order to see his dreams on the end of the Dragons but was refused by Issei who asked him to wait until he had fully recovered. When asked whether he was still with the Qlippoth, he denied it and left.

Crom Cruach visited the Hyoudou Residence in Volume 19 to deliver the egg of a Specter Dragon to repay a debt of gratitude to Tannin as he gave him food and shelter. After meeting Ophis, Crom Cruach challenged her to a fight but she replied that she cannot as she promised to Issei that she wouldn't fight and when asked if there is any way around, Ophis replied that she doesn't know.

In Volume 20, Crom Cruach is seen observing Ophis as she takes care of the Specter Dragon egg. He accepts some bananas from Asia. Then, after Asia tells Issei about Fafnir's current state, Crom Cruach tells them not to worry because Fafnir is a Dragon King and that he is strong enough to survive Rizevim's vicious attack. He is present to watch the security footage of Niðhöggr's intrusion into the Hyoudou Residence. When Issei angrily asks him why he did not get there sooner, he responds that he's only there to observe Ophis and does not say any more than that. During the surprise attack on Agreas, Crom Cruach stops Issei and Rias from fighting Niðhöggr. He then punches Niðhöggr, telling him next time that he would not let anyone interfere with his observation of Ophis. When Issei apologizes to him and tries to bow to him, Crom stops him, telling him that a Heavenly Dragon should not bow to an Evil Dragon. Issei and Asia watch as Crom turns into his enormous dragon form.

In Volume 21, Crom Cruach and Cao Cao arrive together at the war zone in Japan siding with D×D's army to fight against Qlippoth's army of Evil Dragon's, fake Scale Mail's and a body of Trihexa controlled by Apophis.

Red Dragon Emperor of the Blazing Truth × White Dragon Emperor of the Morning Star: The True Dragon(s) of the Kuoh Academy
In Volume 22, Crom Crauch joins Rias Gremory's peerage as her Pawn under the alias of "Mr. Black" for the Rating Game World Tournament.

Powers & Abilities
Immense Strength: Crom Cruach is said to be the most powerful of the Evil Dragons to the point that he is superior to all the other Evil Dragons including Apophis and Azi Dahaka. After the years he spent on training himself back and forth between the Human world and Underworld, Crom Cruach has supposedly attained power that is on par with the Heavenly Dragons. This was proven when he was able to easily fight against both Issei and Vali, the possessors of the Two Heavenly Dragons at the same time just to stall them. He is so strong that he seemed to force Dulio Gesualdo to use his Balance Breaker, despite the fact that Dulio is forbidden to activate it without permission from Michael. In fact, his strength has surpassed that of the power of the Heavenly Dragons in their primes (albeit in their separate prime conditions). In Volume 23, he unleashed an extraordinary aura blast with power output comparable to Issei's Infinity Blaster in Pseudo-Dragon Deification, destroying most of the arena field and leaving a colossal hole in the game field barrier. Crom Cruach is also able to fight on par with Vali in his Diabolos Dragon Lucifer form.

Immense Speed: Crom Cruach has shown to be extremely formidable in terms of speed being able to counter and fend off attacks from Vali who has light speed in his Balance Breaker and Issei who has Welsh Sonic Knight God speed in his Crimson Armor.

Immense Durability: Crom Cruach has shown immense resistance to damage, being able to withstand Issei's Crimson Blaster when combined with Ascalon's Dragon Slayer power with only a torn off wing (albeit Issei only managed to land the blast of one cannon). This is quite a considerable feat as Crom Cruach was never modified to be immune to Dragon Slayers by the Sephiroth Graal. His durability has been vastly enhanced by countless years of training as shown when Crom Cruach could bite down with his dragon mouth to block a replica of Tathlum, a magical weapon that Azazel and Crom Cruach himself stated to be lethal to the Evil Dragon in the past.

Master Hand-to-Hand Combatant: Crom Cruach is immensely well-versed in the art of hand-to-hand combat, being able to fight both Issei in his crimson armor and Vali in his normal Scale Mail at the same time with minimal movements. He was also able to overwhelm Issei in his crimson armor during Qlippoth's invasion of Heaven. He was even able take upper hand in his battle agains Vali in his Diabolos Dragon Lucifer form despine his training wits Son Goku and his superior speed.

Battle Intuition: Due to an overwhelming amount of battle experience, Crom Cruach has developed a sense of intuition that allows him to counter opponents who cannot be tracked through usual methods. His intuition is so great that he was able to counter Vali in his Diabolos Dragon Lucifer when he was not able to dodge Vali's attacks or even see him due to his speed.

Dragon Flames: Crom Cruach can breathe immensely powerful flames. He can widen their range so much that they appear to cover the entire sky, and they are strong enough to melt Vali's Empireo Juggernaut Overdrive armor and break through his Compression Divider.

Shapeshifting: He has the ability to shapeshift from his dragon form to human form. However, according to himself, there's no substantial difference in his battle strength regardless of the form he chooses.

Flight: As a dragon, Crom Cruach can fly using his wings.

Quotes

 * "Bananas really are nice things." (Volume 20)

Trivia

 * Crom Cruach has started to have a liking for bananas after Asia gave him one.
 * Currently, Crom Cruach is the only known major Evil Dragon that isn't either dead or sealed.