666 (Trihexa)

666 (Trihexa) is a legendary being known as the Apocalyptic Beast and is stated to be on par with Great Red and Ophis in her full power. It is the Beast recorded in the Apocalypse.

Appearance
666 has the appearance of a large beast with characteristics coming from different animals (lion, leopard, bear, dragon, etc.) and has seven necks and seven heads and ten horns, as well as seven long thick tails in different shapes, it has four stout arms and two legs that are even thicker than its arms. Its main body is that of a primate leaning forward covered in black fur and what appears to be scales all over its body. Its size is well over several hundred meters long and is larger than Great Red.

The appearance of Trihexa's core described by Issei and Ddraig in Volume 21, it doesn't have 10 horns on its head nor does it have seven heads. It has the appearance of a young boy who is able to sprout six wings (bird, dragon, bat, and various other beasts).

Personality
Not much is known about its personality other than the fact it has only one nature and that is to destroy everything including the Underworld, Human world, Heaven, and other mythological worlds. It's possible it's completely mindless and its only instinct is its nature to destroy everything. Its homicidal nature combined with its immense power made it immensely dangerous to the point that the God of the Bible would have to risk his own life by using numerous forbidden seals to seal it away to prevent it from endangering the World.

History
At some point in the past, the God of the Bible confirmed the existence of 666 that was thought to be unknown and placed thousands of seals on 666, sealing it at the "end of the world". In Volume 16, however, it was revealed that Rizevim and Qlippoth found 666 by using the Sephiroth Graal's ability to come into contact with the principle of life and decided to unseal him with the power of the Holy Relics.

The Legend of Oppai Dragon and his Lively Companions
666 was mentioned in Volume 16 by Rizevim Livan Lucifer who reveals his goal to unseal Trihexa with the use of Sephiroth Graal and Incinerate Anthem to pit him against Great Red.

In Volume 20, 666 first made its appearance as it was found by the trio of Azazel, Vali, and Lilith sleeping at the center of the power chamber of Agreas. Rizevim relocated the beast from the end of the world to Agreas and used the crystal inside it as a power source for unlocking the seals placed on 666; together with the fruit of life, most of its seals were already broken. As a last resort in case of Rizevim's death, he used his soul as the final power source to complete the awakening of the beast. After 666 had fully awakened, it destroyed the ceiling of the floating city and flew up together with an army of mass-produced Boosted Gear Scale Mails. 666 and the armors then left the scene with the legendary Evil Dragons Apophis and Azi Dahaka.

Few days after being unsealed, Trihexa along with the Qlippoth army, dealt massive damage to several of the mythologies, eliminating many Gods in the process. Trihexa later splits its heads into seven bodies attacking multiple locations including Europe and Japan. Through the efforts of the myths working together, the Sephiroth Graal was reclaimed from Qlippoth and Trihexa had its movement sealed through the magic equation formulated by Rossweisse. Trihexa, however, manages to release all of its cores before its movement was sealed with one of the cores appearing before Issei Hyoudou. The core that appeared before Issei then battled Issei and Sirzechs who came to Issei's assistance as both of them fail to deal any damage to the legendary beast. The battle, however, came to a swift end as Sirzechs along with the leaders of many mythologies sealing themselves with 666 in an Isolation Barrier Field, trapping 666 in the barrier as the beast now battles the leaders inside the barrier.

Power & Abilities
Immense Strength: 666's powers were initially largely unknown due to being sealed for many years. 666 has power on par with Great Red and Ophis in her prime; a clash between both Trihexa and Great Red is feared because of the potential damage it could inflict to the world due to their strength with Azazel believing that a clash between them will result in the end of the world. Rizevim stated that it took thousands of forbidden level seals for the God of the Bible to seal it away. Upon gazing it for the first time, Azazel notes that just its aura alone is enough to make a normal person go crazy. According to Shiva, only Ophis at full power and Great Red can destroy it as 666's absolute overwhelming power made it impossible for Shiva; who is an immensely powerful God, to destroy it. In a matter of days after being unsealed, it managed to cause great damage to multiple myths.

Fire Breath: 666 can fire a powerful fireball from one of its heads.

High Speed Regeneration: Aside from its nigh indestructible skin, Trihexa possesses high speed regeneration, being able to heal itself in an instant if any parts of its body is damaged. Its tremendous regeneration allow it to easily survive immensely powerful attacks from even god class beings, even Sirzechs a Super Devil in his true form could not inflict any permanent damage on Trihexa.

Body-Splitting: Trihexa can split each of its heads into seven different bodies.

Flight: Trihexa is shown capable of flying without wings. Although the core of Trihexa is able to sprout six wings (bird, dragon, bat, and various other beasts).

Mass Boosted Gear production: With the help of the Khaos Brigade's modifications with the Sephiroth Graal, Trihexa can mass produce Boosted Gear and Juggernaut Drive armors.

Core Expulsion: 666 has shown the ability to release its core. As he demonstrated in Volume 21, as Trihexa was curious as it sensed both Great Red's and Ophis' powers coming from Issei.