666 (Trihexa)

666 (Trihexa) is a legendary being known as the Apocalyptic Civil Beast and Emperor Beast of the Invasion Apocalypse. At its full power, it is stated to be on par with Scarlet Grand, Ophis and Wagyl. Also, it is the Beast recorded in the Apocalypse.

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

The appearance of Trihexa's core is described by Arthur and Ddraig in Volume 21 as neither having seven heads or having 10 horns, but having the appearance of a young boy who is able to sprout six wings (bird, dragon, bat, and various other beasts) instead.

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

Despite its supposedly savage nature, it seems to have an interest in Scarlet Grand, Ophis and Wagyl. This is evidenced by how it was attracted to Arthur upon sensing their power in him. This could be because both Scarlet Grand, Ophis and Wagyl are beings on par with Trihexa.

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 forbidden seals on it, sealing it at the "end of the world". In Volume 16 however, it was revealed that Drakon and Qlippoth found 666 by using the Twilight Graal's ability to come into contact with the principle of life and decided to unseal him with the power of the Holy Relics.

Volume 16
666 was mentioned in Volume 16 by Drakon La Leviathan who then reveals his goal to unseal Trihexa through the use of the Twilight Graal, two fragments of the original Holy Grail and the Shroud of Turin to pit him against Scarlet Grand.

Volume 20
In Volume 22, 666 first made its first appearance when it was found by the trio of Azazel, Vali, and Lilith sleeping at the center of the power chamber of Agreas. Drakon 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. This, together with the fruit of life, succeeded in breaking most of its seals. As a last resort in case of Drakon's and Rizevim Livan Lucifer's deaths, they used their souls 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 Pump and Divine Dividing Scale Mails. 666 and the armors then left the scene with the legendary Evil Dragons, Apophis and Azi Dahaka, and the son of the original Asmodeus, Cythraul Sohn Asmodeus in tow.

Volume 21
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, Africa and Japan. Through the efforts of the myths working together, the Twilight Graal was reclaimed from Qlippoth and Trihexa had its movement sealed through the magic equation formulated by Waltraute, Ashe Elizabeth and Rossweisse Brynnhildr. Trihexa, however, manages to release all of its cores before its movement was sealed, with one of the cores appearing before Arthur. However, despite the core engaging Athut and Percival, the latter who had come for Arthur's assistance, both of them failed to deal any damage to the legendary Beast. The battle, however, came to a swift end when Percival along with the leaders of many mythologies sealed themselves with 666 in the 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 Scarlet Grand, Ophis and Wagyl in its prime; a clash between both Trihexa and Scarlet Grand 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. In fact, it is such a true monster that it could easily destroy the entire world on its own. Drakon 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 in her god form, Wagyl at full power and Scarlet Grand 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 massive damage to multiple mythological factions, nearly completely wiping out Heaven, Olympus, Grigori, and Asgard.

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 and is able to heal itself in an instant if any parts of its body were damaged, being able to regenerate even if turned to ashes. Due to its immense regeneration, Trihexa can easily survive immensely powerful attacks to the point the Overdrive of extremely powerful Longinus Possessors such as Cao Cao, Marcello, Tobio, Arthur, and Vali could not inflict any permanent damage on Trihexa's body. According to Percival, even with the combined force of the numerous Gods of various mythological factions, Azazel, Asriel, Michael, Galahad, Jin and four of the current Satans including Percival and Myrddin, two Super Devils, it will take an enormous amount of time to be able to defeat or even seal Trihexa due to its tremendous regeneration powers.

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 Pump and Divine Dividing Production: With the help of Devil Hand's modifications with the Twilight Graal, Trihexa can mass produce Greater Boost, Divine Dividing and Juggernaut Drive armors. It was gone after Nanao, Hinami, and Valerie got back her Grail.

Core Expulsion: 666 has shown the ability to release its core. It demonstrated this in Volume 21 when one of its cores appeared before Arthur due to Trihexa's curiosity when it sensed Scarlet Grand's, Ophis' and Wagyl's powers coming from him.

Trivia

 * The name "Trihexa" can be broken up into two parts: "Tri" which means "three", and "Hexa" which means "six". So "Trihexa" can be interpreted as "Three Sixes" which can refer to the name of 666, which has three sixes.