Kraken Isaak

Kraken Isaac (クラーケンのアイザック, Kurāken no Aizakku) is the Marina General of Kraken, and the guardian of the Arctic Ocean Mammoth Pillar. His notable personality traits are that of a cold and ruthless man, who has no emotion save for malice, and fights for the ideal of true justice, much akin to the concept of means justified by ends. Kraken Isaac shares a past with Cygnus Hyoga and thus becomes an important figure in the Saint's life.

Technique

 * Aurora Borealis: This technique was almost on par with Aquarius Camus' Aurora Execution, but somewhat weaker. However, this technique was much stronger than almost all the techniques under Cygnus Hyoga's knowledge. Most of Isaac's attacks are ice based; like Hyoga, he can also project his Cosmo to freeze objects, as shown by his first appearance when he instantly turned the wind into snow. Aurora Borealis is Isaac's strongest attack, powerful enough to penetrate Hyoga's defenses, and is the technique he employs that makes best use of the cold.

Training in Siberia
Isaac, like Hyoga, was also an orphan under the guidance of Aquarius Camus (the Crystal Saint in the anime), who was also to receive training in order to become a Saint. Hyoga first met Isaac as a child. Both children enjoyed each other's passion to become Saints, and soon became best friends. As with any training to be a Saint, the tests were harsh, and the weather in Siberia was almost in the extreme subzero temperatures. However, no matter how harsh or how severe the training was, together, as friends, they survived.

Hyoga admired Isaac because it was his strong will that enabled him to surpass any obstacle. Isaac admired the sea monster called Kraken, whose terrible anger reigned upon pirates and those who did evil. Isaac had clearly a stronger Cosmo than Hyoga, and in his heart Isaac yearned to be a true Saint like their teacher. Isaac took the training to become a worthy Saint to bring peace to the Earth, just like his master, the person he looked up to the most. Isaac once commented he would like Hyoga to follow the footsteps of their teacher and be as strong as he is. However, Hyoga did not share the same passion, and had personal reasons to become a Saint.

The Mystery Behind The Scarred Eye
Hyoga never cared about being a Saint, as a matter of fact: there was a deeper motive behind his actions to become one. He was fortunate to train in East Siberia, coinciding with the place where his mother's grave was located. The ship that had sunk many years ago still contained Hyoga's mother Natassia's body, trapped under the very thick ice. In his current state, Hyoga did not have the necessary strength to break through the ice, let alone swim the incredible depth to reach the ship. Only as a Saint could Hyoga gather enough strength to break through the ice.

After years of training, when Isaac became aware of Hyoga's true motives, he rapidly began attacking Hyoga, scolding him that a Saint must never use his own power for his own selfish reasons. But what really angered him was that Hyoga never truly cared about becoming a Saint, nor the ideals upheld by their teacher. Isaac lashed out in anger, and started beating Hyoga until he finally stopped. Isaac realized there was nothing that he could say that would stop Hyoga. Disgusted and bitterly disappointed, Isaac left Hyoga, but warned him of the strong current at the depth Hyoga wanted to reach.

Hyoga was finally free to achieve his goal. He broke through the ice and swam the great depth to recover his mother's body. Overwhelmed by his emotions, Hyoga contemplated the beautiful face of the woman who had died to save his life many years ago. The cold had preserved Natassia perfectly. Hyoga, finally content, decided to head back to the surface, but he was caught under the terrible current Isaac had warned him about. Not wanting to be swept away from his mother, Hyoga held on to the ropes of the ship, becoming entangled in them.

On his way back to check on Hyoga, Isaac found that despite his warning, Hyoga had taken the dive, and realized his friend was trapped. Seeing that the deep devotion Hyoga had for his mother helped him hold on to the ropes and survive in the freezing water without air, despite the slim chance of making it back to the surface, Isaac realized that Hyoga could indeed become a worthy Saint of Athena, if he gave his training the same devotion.

Isaac recovered Hyoga's body, but they were both pulled under by the current; in the process, Isaac's left eye was pierced by a sharp piece of ice. Somehow, Isaac managed to save Hyoga and they swam for the surface. However, they were trapped under the ice that sealed the hole Hyoga had made. Isaac burned his remaining Cosmo to punch through the ice and save Hyoga by throwing him out of the frigid waters. Sadly, due to blood loss from his eye injury, mixed with fatigue and numbness from struggling against the gelid water, Isaac no longer had the power to save himself, and was swept away by the current. Hyoga's screams for his friend faded to nothing as Isaac's body was tossed into the cold depths.

Delivered from certain death to Poseidon's Undersea Temple
Isaac closed his remaining eye and waited for an icy death to consume him. But an imposing shadowy figure that appeared to be the mythical Kraken seemed to loom over his body and enveloped him in its dark cloak. Isaac soon roused in what he realized was a mythical, holy place, said to be the legendary Undersea Sanctuary of Atlantis, the realm of the Emperor of the Seas: Poseidon. It was Poseidon's will that saved Isaac's life, and had granted him a second chance. Isaac soon learned about Poseidon's dream of the perfect world for humans. The current world had become polluted and vilified by humans, and as such, a second great flooding would wash away everything in order to create a new Utopian society.

Isaac pledged his loyalty and his life to Julian Solo, who was the vessel chosen by Poseidon to reincarnate in this era, and became the Guardian of the Arctic Sea Mammoth Pillar.

Kraken Isaac, the General of the Arctic Sea
As the Kraken General, Isaac had command over the immense army of Marinas whose loyalty only resided in Poseidon. This also fit perfectly with the ideals he held since he was a child. Soon, horrible news reached Isaac from the land, fueling his already deep hatred towards humanity and their transgressions:

Saints have been reborn, signaling the coming of new Holy Wars, but betrayal between the Sanctuary and Athena had led to deaths of many Saints(Most of the Silver Saints assassins sent by the Pope, had been killed by this time as their mission was to kill Saori Kido and her Bronze Saints).

The war against Sanctuary had also led to many deaths, including people who were once important in Isaac's life, such as his teacher, the Crystal Saint, who was under the manipulation of the Pope's deadly Genrōmaōken, which sent him into madness and ultimately to his death at his student Cygnus Hyoga's hands (only in the anime adaptation).

The bloodshed continued as Hyoga also defeated and killed the venerable Gold Saint Aquarius Camus in the Twelve Zodiac Temples conflict. Soon enough, Athena was placed under the Main Breadwinner, which was found behind Poseidon's Quarters. As expected, the Bronze Saints were sent to assist her and stop the world from being destroyed by the floods caused by Poseidon. By this time, four of the Pillars had already been destroyed, leaving three Pillars left: The Pillar of the Arctic Ocean, The Pillar of the North Atlantic Ocean, and the Pillar of South Atlantic Ocean. Hyoga was headed for the Pillar of the Arctic Ocean, where his old friend was waiting to meet him.

As Hyoga approached the Arctic Sea Pillar, he was confronted by yet another face of his past; this time, it was Isaac himself. Isaac projected his Cosmo and instantly created snow, signaling their old friendship was still very important to Isaac. Hyoga began to weep, as he had thought Isaac had died on that fateful day. Isaac greeted his former friend with an attack, and remarked that Isaac did die that day: he was now Kraken Isaac, Marina General of Poseidon. He unleashed his deadly attack, Aurora Borealis, which nearly blew Hyoga away. The Cygnus Saint couldn't bring himself to fight back because he was overwhelmed by nostalgic feelings for his childhood friend, and guilt, for he was responsible for his downfall. Hyoga forfeit his life and demanded that Isaac take his left eye, and Isaac did not hesitate to do so, instantly piercing at Hyoga's eye and leaving him with blood loss. Strangely, Isaac only managed to hurt Hyoga's eyelid, leaving his eye unharmed.

As Hyoga contemplated his last moments of life, he asked the true reason behind why Isaac had become a Marina General, if he meant to be a Saint. His former friend only replied that Poseidon saved his life, and he became disgusted at the world that was full of hate and meaningless fighting. He also degraded his former teacher, the Crystal Saint and Aquarius Camus, calling them weaklings. This angered Hyoga and gave him a chance to retaliate, but Isaac clearly possessed a stronger Cosmo, fueled by a deep grudge, hatred, and emotionless ruthlessness.

Hyoga was again defeated, but Isaac was distracted before he killed the Bronze Saint. He noticed Kiki, the apprentice of Aries Mu, had sent to the battle with the Gold Cloth of Libra, the weapons of which were capable of demolishing the Sea Pillars. Thus Isaac turned his wrath on Kiki, forcing Hyoga to rescue the apprentice, and scolded Isaac for raising his fist against a child. Isaac was indifferent; in his eyes, all enemies of Poseidon had to die, be it man, woman or child. Infuriated, Hyoga burned his Cosmo, once again awakening his Seventh Sense; in doing so, the Cygnus Bronze Cloth started to emit a mysterious golden radiance. He prepared a Diamond Dust attack, which effectively took Isaac off guard, and made him prepare his deadliest attack, but Hyoga struck back with his Aurora Execution, which completely decimated Isaac's Marina Scales.

Defeated at last, Isaac congratulated Hyoga in this victory, happy to discover Hyoga had grown so much, perhaps even beyond their teacher, and wished him luck on his journey. Again he warned his old friend of the danger again: someone whose name must be familiar to them by now. Despite Hyoga's pleas that he conserve his strength, Isaac told his friend the next enemy possessed a truly powerful Cosmo as the Guardian of the North Atlantic Pillar: the Sea Dragon General. Isaac succumbed to death soon after.

Trivia

 * The Kraken is a creature of Norse/Germanic myth and not from Greek or Finnish mythology. It is quite possible that there was confusion with Cetus, the sea monster that was devastating the land of Cepheus, named after Andromeda's father King Cepheus. This is confirmed with the shape of the Marina Scale being reminiscent of a manta ray as opposed to a cephalopod like the Kraken.
 * The moment where Isaac beats Kiki is one of the only moments in the series that a Saint/Saint-like opponent attacks a non-Saint person. In all the other occasions Saints only fight other Saints/Saint-like enemies.