Ouken

 (オウケン, Ouken) is a character in Ousama Ranking and its anime adaption. He is the former Commander of the Order of the Underworld, a member of the Underworld royal family, and such a fierce warrior that he's known as the Sword King of the Underworld.

He was imprisoned in the Underworld until being freed by Miranjo.

Appearance
Ouken is a somewhat tall, well-built man with black hair, black eyes, and a black moustache. He wears head-to-toe silver plate armor with a shaggy black fur cape running down his back, and a shaggy black pelt around his waist.

Rather than a normal visor, Ouken's helmet features an intricately-wrought face with a strange, slightly puckered mouth, completely black eyes, and long devil horns protruding from its top. As an immortal Ouken wore his complete suit of armor at all times, and was even capable of regenerating it when it was destroyed.

Personality
Originally, Ouken was a kind and compassionate man, and was considered the most noble of his brothers. Ouken founded the Order of the Underworld as a direct consequence of his brother's revolution, resolving to create a kind yet mighty order of knights to combat the sadism he had witnessed in their ranks.

As an immortal Ouken became deeply disturbed, and seemed to relish acts of violence so much that he trembled in anticipation of doing them. Moreover, after attacking an opponent, Ouken liked to crouch down and observe them as they died, refusing to deal a killing blow.

The Curse of Immortality
One of the three brothers who conspired to overthrow their father Satun, the original king of the Underworld, Ouken was a kind-hearted, loving man who wished to found an order of knights that shared his values. On his 25th birthday he acquired true immortality, an ability that has slowly destroyed his humanity, making him a remorseless monster that enjoys inflicting pain on others.

Coup of the Bosse Kingdom
This madness forced Ouken's brothers to imprison him in the Underworld, where he remained until being freed by Miranjo to conquer the Bosse Kingdom.

While all the prisoners are notorious in their own right, those familiar with Ouken seem to openly fear him, and it's suggested that he is, by far, the most dangerous of the group. He easily dispatched Kingbo, another prisoner who was a former King and a very capable warrior, in a brief altercation.

Ouken was an enormous threat on the battlefield, easily dispatching Queen Hilling's personal guard, Anne, in a few short moves. If not for Hilling's healing magic Anne would have died. After the initial altercation Ouken began walking towards the Bosse Kingdom's capital city, presumably to murder more innocents.

Luckily Ouken was intercepted by Despa and a detachment of the Order of the Underworld, who managed to subdue Ouken with the assistance of a massive bolt of lightning sent by King Desha. Ouken was tied up and readied for transport back to the Underworld. The conflict appeared to be over, until Ouken literally destroyed his own bones to escape his bonds, and began his counter-attack.

Battle with Bojji
Miranjo recalled Ouken to her side as the tide of the battle began to turn against her. In short order Ouken slayed the remaining Underworld prisoners, and easily put down Apeas as well. He seemed invincible, until Bojji arrived on the scene and confronted him. Though outclassed by Bojji's swordsmanship, Ouken's immortal body allowed him to quickly recover from all of Bojji's disabling attacks. Ouken was able to slowly accumulate minor injuries on Bojji's body, giving him the advantage in the fight.

When things looked most dire for Bojji an enraged Kage swelled to enormous size and swallowed Ouken whole, providing a brief delay in the fight which allowed the Big Four to catch up with Ouken. Now squaring off against 4 master combatants, Ouken again was quickly and repeatedly disabled by their techniques, but again, his immortal body allowed him to recover almost instantly. At one point the Big Four even managed to sever his body parts, holding them separately to prevent his regeneration, but the black bile that animates Ouken's immortal body was able to force the parts back together anyway.

Battle with Bosse
In time Ouken managed to disable every warrior on the field, his immortality making him seem invincible. Then the reincarnated Bosse joined the fight. After quickly reviving his warriors, Bosse made terrifyingly short work of Ouken, repeatedly smashing his body to small bits to keep him disabled. Realizing that no amount of damage would ever permanently defeat Ouken, Bosse briefly tapped the ground searching for a large solid stone. When he found one he unearthed it and punched a small hole in its center. Then Bosse crushed the fragments of Ouken's armor with his massive strength, turning the immortal swordsman into a small ball of metal.

Bosse stuffed the ball into the unearthed stone, and sealed the hole with more rocks, trapping Ouken's body in a space too narrow for it to regenerate.

Aftermath
A short time later, in the aftermath of the attempted coup of the Bosse Kingdom, Ouken was freed by a spiteful Kingbo (who had survived their first encounter). A spiteful Kingbo allowed Ouken's body to regenerate, then cut off his head with a sword strike and pitched it far away, beyond the range of Ouken's regeneration.

Return
Ouken's headless body became relatively passive, and slowly shambled in the direction of its head. Despa and the Order of the Underworld followed him closely, needing to restore Ouken but planning to immediately subdue him once again. At length, the party arrived at a small lake in the countryside, where they discovered Ouken's head had been swallowed by a humongous catfish. Ouken's body heedlessly shoved itself into the catfish's mouth to retrieve its head.

Concurrently, Ouken's older brother Desha was named the #1 ranked king, and was allowed to enter the Divine Treasure Vault. Desha had accepted the position specifically to gain access to the vault, believing it contained an artifact that could cure Ouken's immortality. Ultimately Desha chose to make a wish with an imprisoned demon, sacrificing his memories to restore Ouken's mortality.

Ouken was restored to his former self, but Desha's fate remains mysterious.

Desha
Ouken and Desha appear to have had a good relationship. Ouken resolved to remain with Desha's revolution even after witnessing the sadism of some of Desha's troops, presumably for the greater good of the Underworld. Desha appears to have appreciated this, and remained loyal to Ouken even after his brother became a depraved immortal.

When Desha finally found a means of curing Ouken's immortality he immediately pursued it, even going so far as to sacrifice his own memories to restore his younger brother.

Despa
Despa and Ouken also appear to have had a good relationship. Ouken was Despa's first student, and Despa considers his brother to be his greatest pupil. Though Ouken largely discarded his brother's training when he went mad, Despa's training ran so deep that Ouken was even able to selectively use it after losing his mind.

After the disappearance of Desha, Despa unreservedly forwarded Ouken as Desha's successor, feeling his younger brother would be a better king than he.

Master Swordsman
Ouken is a master swordsman, and considered the pinnacle of swordsmanship in the Underworld. Similar to Bojji, Ouken has undergone extensive training with his older brother, Despa, and Despa considers his brother his greatest pupil. Ouken's title, "Sword King of the Underworld," suggests he is at least as powerful as a king.

Immortal Ouken: As a immortal Ouken largely discarded Despa's teachings and developed a particularly sadistic sword style. Ouken would attack an opponent's non-vital points, disabling them but also ensuring their death would be as slow and painful as possible.

Mortal Ouken: Once he regained his mortality Ouken's true skill returned, and he is once again able to call upon his knowledge and experience to fight intelligently. Despa believes that Ouken is now nigh-invincible, presumably meaning he has supplanted Bojji as the strongest man in the world. Since regaining his wits Ouken has even defeated a God in single combat.

Desha's Teachings
Ouken has received special training from his eldest brother, Desha, as well. The nature of this training is unknown to most, but Despa believes it has made Ouken his eldest brother's most worthy successor, and the only other man capable of leading the Underworld.

Shirasampe
An initially-mysterious technique that seemed to paralyze his opponents. Ouken's "shirasampe" was later revealed to be a devastatingly simple attack. Ouken throws small objects at his opponent's vital spots with blinding speed and accuracy, and the impact of the pebble temporarily stuns his opponent. This attack is so fast most can't even perceive it, and to date only Bojji has successfully dodged it. Probably this technique is on higher level since he regained his humanity.

Superhuman Strength
Ouken is many times stronger than the average human, able to shatter stone walls with his bare hands and overcome eight trained knights with raw power alone.

Indomitable Will
Ouken was able to repel an attempt to possess his body by his father, the God Satun. It's also suggested that Ouken's willpower allowed him to resist the dehumanizing effects of his immortality for years, though he did inevitably succumb to them.

Immortality
Ouken is a demigod, or a human/god hybrid. Though he initially believed he hadn't inherited any of his father's power, on his 25th birthday he discovered that his body would rapidly heal any injury. Ouken's power had manifested as immortality, the very ability that his father coveted.

Immortality is considered a curse in the Underworld. It's believed that if you can never die you will inevitably lose all reason to live, and will slowly descend into an endless madness. This madness took root in Ouken, turning him from a kind, noble man into a remorseless killing machine that lacked all reason. This lack of sanity made Ouken uniquely susceptible to mental attack, as shown when Miranjo very easily put him in her thrall.

Ouken's body could not be killed, and would quickly heal any wounds, even regenerating destroyed parts. This mysterious ability extended to Ouken's sword and armor, which Ouken could reform at will, even if they were shattered. This suggests Ouken considered his sword and armor a part of his body. Indeed, the only force that could disable Ouken for a significant amount of time was magic, and even then if his head was unaffected its effects were drastically reduced.

Note: Ouken no longer possesses immortality, and has regained his senses.

Trivia

 * 's name likely derives from the Japanese word for "sword king" (剣王, Ken'ou).