Ragnarok

Ragnarok (ラグナロク) was a demon who was a ruler hailing from the 4th Realm. He was summoned by Mordred during the "Black Rose Incident" to combat Shadow and was ultimately slain by the latter.

Appearance
It bore the visage of a bluish-black demon, reminiscent of a bat, boasting a colossal physique akin to the demon king Diabolos. With a menacing fanged maw, it possessed four razor-sharp claws protruding from the ends of its sinewy, blood-hued limbs. Its sturdy legs featured three formidable fingers each, and its entire form blazed with fiery intensity. Additionally, a pair of colossal wings adorned its frame, granting it the power of flight.

Personality
Despite being a magical beast and a demon king, Ragnarok's behavior often mirrors that of a creature driven by primal instincts. He strikes at his own discretion and, occasionally, when provoked. Shadow likened him to a being lacking in intellectual prowess, drawing a comparison to Delta, as Ragnarok rarely harnesses his magical abilities and struggles to wield them effectively.

Being a rather simple-minded magical beast, the Cult of Diablos found a way to partially control him for their benefit.

Background
When the Black Rose incident occurred, the demon king Ragnarok had the opportunity to briefly appear in Oriana Kingdom but was repelled by the Cult of Diablos, who were very interested in the phenomena of the so-called "Black Rose" and that there is more than one world, apart from the one inhabited by the people of the world where Cid reincarnated, (this was long before Cid reincarnated).

Through a treaty that was made between Oriana's past kings and the leaders of the cult, a calamity was avoided thanks to the cult. But, in exchange for the royal family having to hand over their royal daughters, since Oriana's royal family has a bond of blood with the human Heroin, and the kingdom were to give a majority of their tax revenue to them, resulting in the kingdom to heavily invest on the arts. Also, the cult manipulating the church to vilify their kingdoms Dark Knights and the kingdom basically became a cult's puppet.

Oriana's "Black Rose" Civil War Wedding Incident
Ragnarok is summoned again to the magical world where Oriana's kingdom was there, through the "Black Rose" portal using the "Ring of Succession" that Rose Oriana wore at her wedding, which was really the key to activate "the Black Rose". Then, it begins to generate chaos but quickly loses one of its wings at the hands of Shadow, and they begin fighting to the death outside the capital, which ultimately results in his death at the hands of Shadow as he cutting every demonic members that falls near the battle that Mordred had against Epsilon, Beta, and Rose, who was watching how they fought.

Powers & Abilities
Ragnarok boasts formidable brute strength, magical prowess, and a ferocity that approaches the level of the demon king of Diabolos. However, he appears to lack rapid self-healing abilities and the strategic intelligence to utilize his magical powers for self-preservation. Nonetheless, while Ragnarok may not be as frail as Elizabeth, he met his demise rather easily at the hands of Shadow.

Super Demonic Prowess
Ragnarok wields a demonic force of such immense magnitude that a single strike from it can obliterate a dozen houses or buildings, leaving behind nothing but a colossal crater. Its remarkable speed enables it to unleash consecutive, tireless barrages of these devastating blows, capable of decimating an entire ordinary city with ease. Simultaneously, Ragnarok can generate a potent albeit localized tremor within the aurea, utilizing the force of its legs and sheer mass.

During Shadow's confrontation with Ragnarok, he astoundingly evaded the demon's formidable onslaught, though not without some surprise. In the end, the entire Midgar snowfield was transformed into a vast expanse of scorched earth. Shadow conjectured that had their battle unfolded within the capital of the kingdom of Oriana, the city would likely have been reduced to rubble mere seconds after their clash commenced.

Demonic Biomutation
Ragnarok possesses a profoundly mutated demonic biology. Any living being, be it an animal or a person of any race, who consumes its blood or devours its flesh, undergoes a drastic demonic transformation. This metamorphosis results in the transformation into an infernal demon, sharing a semblance of Ragnarok's imposing appearance and wielding tremendous magical power. However, this dark empowerment comes at the cost of potential loss of consciousness.

Remarkably, even in death, Ragnarok's demonic flesh and blood retain their potency for an almost indefinite duration, albeit not to the extent of Demon Diabolos's body. An illustrative example of this occurred when Modred, confronted with the apparent defeat of Ragnarok at the hands of Shadow, succumbed to a mixture of fear and rage. In his desperation, Modred consumed Ragnarok's demonic meat, triggering a transformation into a formidable demon akin to Ragnarok, boasting two-thirds to three-quarters of the demon's power. Nonetheless, this empowered state proved fleeting, as Modred ultimately met his demise at the hands of Shadow and his formidable "I am atomic sword" technique.

Flight Capacity
Ragnarok possesses a natural ability to take to the skies, courtesy of his massive demonic wings. This attribute enables him to achieve astonishing supersonic speeds in a matter of seconds, although the extent of his return speed remains a mystery. It was during a moment when Ragnarok's guard was momentarily lowered that Shadow seized the opportunity to sever one of his wings, effectively grounding him. (Speculation suggests this strategic move aimed to prevent Ragnarok from wreaking havoc in neighbouring regions, evading capture, or initiating aerial conflicts notorious for their potential collateral damage on terra firma.)

Body on fire
Ragnarok's entire form is enshrouded in an infernal blaze, emanating deadly temperatures capable of liquefying solid rock and proving fatal to any warrior or magical knight who ventures within a meter's range. This searing heat can be harnessed by Ragnarok to enhance the power of his punches, and when his anger surges, his body temperature escalates even further. Shadow stands as a remarkable exception, as he was the sole individual able to confront Ragnarok without succumbing to the searing heat, thanks to his protective slime bodysuit and his exceptional control over it.

Magic
Speculations abound regarding Ragnarok's magical prowess, suggesting that he possesses the potential to stand on par with the formidable demon Diabolos, the reigning monarch of the fourth demonic realm. While his intelligence might not be a standout trait, Ragnarok commands the unique capability to emit bursts of magical energy from both his maw, akin to a dragon, and his wings.

In addition to these formidable talents, Ragnarok exhibits a notable capacity for self-healing. However, in comparison to Diabolos, his regenerative abilities are pale, as he lacks the capacity to magically regenerate severed limbs to the same extent as the demon king.

Demon Breath
Ragnarok wields a formidable ability to concentrate his magical energy within his maw, unleashing a devastating demonic breath that possesses the potential to obliterate anything in its path. Shadow, though confident in his capacity to withstand this attack, wisely chose to avoid facing Ragnarok's unleashed might out of concern that the residual effects could wreak havoc upon Oriana’s capital, a decision driven by the desire to avert needless destruction.

Trivia

 * The name Ragnarok, means the end of the era of norse gods, of norse mythology.
 * When Shadow annihilated the demon king Ragnarok leaving only one of his members, he did it in a similar way to Olivier when she cut off one of the arms of the demon king, Diabolos. But, the difference is that Olivier defeated him with the help of her fellow heroes, while Shadow did it alone.
 * Ragnarok is classified as a more dangerous existence than Elizabeth, since if she could sweep 3 countries in the 3 days that there was, the red moon, Ragnarok by his side can destroy several countries, possibly even a continent in a few days, if he uses his magical power.
 * Being a very old existence, and mainly very ancestral, it is speculated that this demon has several eons of existence, more than any living-level creature in the world, up to the present date.
 * Ragnarok is one of the enemies, aside from Mist Dragon and Elizabeth, that forced Shadow to get a little serious, in the official part. being the third in it.
 * According to Shadow words, if he had fought directly in a battle of brute force, obviously, he would have lost against Ragnarok.
 * Shadow granted him the title of; 'He more ignorant than Delta.'
 * Mordred is the only one of "the 12 knights of the round table", of the Cult of Diabolos, who consumed the flesh of the Demon King Ragnarok, also managing to be the only one capable of controlling all his magical power without losing control over it, in part, and not going crazy with magical power, for the most part, except in his frenzy of wild rage.