Kokuo in Naruto

Hagoromo created Isobu and the other tailed beasts. It splits the energy of a powerful Ten-Tail into Nine-Tailed Beasts, and Isobu is one of those Tailed Beasts. Hagoromo told the tailed beasts that they were connected and would be reunited one day. In the anime, Hagoromo arranged for Isobu to be kept safe in a Land of Water region part.

During the First Shinobi World War, Hashirama Senju captured eight-tailed beasts. To establish friendly relations and maintain a balance of power among the newly formed ninja villages, he sold two of these tailed beasts, Kokuo and Son Goku, to the village of Iwagakure during a gathering of the Five Kage.

Fourth Shinobi World War: Climax Arc

When Obito controlled all 7 tails beasts to follow him in the Fourth Shinobi World War, he used them to fight against Naruto and Killer B, Five Tails was one of the tail beasts.

When Eight Tailed got the upper hand against the other beasts, Obito forced Han, the former Jinchuriki of Kokuo, to transform into its full form and attack Gyuki (Eight-Tails), which he did with his horn, injuring the Gyuki.

Tobi lost control over Five Tails which made the Five Tails charge toward Tobi (Obito Uchiha) but then Tobi used his seal rod chains to control Kokuo once again.

After Son Goku resealed into the Demonic Statue of the Outer Path. Tobi forces Han, the host of the Five-Tails, to fully transform and attack Naruto and Killer B alongside Might Guy and Kakashi Hatake. When Naruto was trying to pull out the metal rods which connect to the chains of the beast, Kokuo came to attack Eight Tails, but then Eight Tails smashed him away with a punch.

As the opposing tailed beasts prepare to attack the shinobi, Naruto, who has grown stronger and can now control the Nine-Tails, intervenes to prevent further destruction. His actions showcase his improved abilities and cooperation with his tailed beast. When the tailed beasts, including the Five-Tails, unleash a powerful attack known as the Tailed Beast Ball. Naruto and the Nine-Tails respond with their own Tailed Beast Ball to counter it to save themselves.

Freeing the Tailed Beasts

The tailed beasts were freed from the control of Obito Uchiha, who had been manipulating them. They joined the fight against the Ten-Tails, a powerful enemy. This was a significant turning point in the war.

Kokuo, along with the other tailed beasts (except for Gyūki and Shukaku), confronted the Ten-Tails when it focused on Naruto. This led to the Ten-Tails undergoing further transformation. Kokuō was separated from Obito with the help of the Allied Shinobi Forces, granting it freedom.

As Madara approached the tailed beasts, Shukaku and Gaara used sand bullets to restrain him. The tailed beasts attacked Madara, creating an opportunity for Shukaku and Gaara to use the Desert Layered Imperial Funeral Seal. However, Madara escaped using his Susanoo.

Naruto, in Tailed Beast Mode, held Madara down, and Kokuō and the other tailed beasts joined in to increase the damage. Madara survived their attacks and retreated. He obtained a Rinnegan eye from a White Zetsu clone, summoned the Demonic Statue of the Outer Path from Obito's body, and used the Rinnegan to repel the tailed beasts. He then chained them up and sealed them back into the statue.

Later, the chakra that Kokuō transferred to Naruto earlier manifested within Naruto's subconscious, along with the other tailed beasts. They spoke to Naruto and Hagoromo Otsutsuki, expressing their belief that Naruto was the child of prophecy.

Kaguya's resurrection

Kaguya Otsutsuki, resurrects through Madara's body which was manipulated by the Black Zetsu to become the Jinchuriki of Ten-Tails. The tailed beasts, including the Five-Tails, helped Naruto and Sasuke in the battle against Kaguya. They shared their power with Naruto and Sasuke, which was essential in defeating Kaguya.

After Hagoromo and the previous Kage brought the tailed beasts and Team 7 back to the real world, the tailed beasts began talking about their future plans now that they were free. Kokuo, one of the tailed beasts, expressed its desire to live quietly in the forests.

However, Sasuke had different ideas. He revealed his intentions to remove anyone who might oppose his plan for a world revolution to change the current shinobi system. This meant he wanted to kill the current leaders (Kage) and the tailed beasts.

Sasuke quickly used his Rinnegan to control the tailed beasts and sealed them inside powerful structures called Chibaku Tensei. But Naruto, determined to save them, reassured the tailed beasts.

After Naruto managed to defeat Sasuke and change his ways, the two of them undid a powerful genjutsu called the Infinite Tsukuyomi. This released Kokuo and the other tailed beasts from their prisons, granting them their freedom once again.

New Era - One-Tail Escort Arc

In this arc, Urashiki Otsutsuki targeted the tailed beasts, including the Kokuo, for their chakra. Naruto tried to organize a meeting with them, but some tailed beasts were afraid of being captured again and refused to attend. Kawaki Arc: In the anime, Kokuo, the Kokuo, sensed the loss of Kurama's chakra after it sacrificed itself in the battle against Isshiki Otsutsuki.

Video Games

Kokuo shows up as a tough enemy in games like "Naruto: Ultimate Ninja Storm" and "Naruto: Rise of a Ninja." There's also a fake version of Kokuo players can battle in "Naruto Shippuden: Kizuna Drive." For those that want to play as Kokuo, they can do so as well! In some games like the "Ultimate Ninja" series, where players can choose Utakata and transform it into Saiken.

Gamers can play as Isobu in both its small and big forms in some games, but in others like "Ultimate Ninja Storm Revolution" and "Ultimate Ninja Storm 4," you can only be the big version of Saiken.

Kokuo's role in "Naruto: The Last" movie

In the movie, Kokuo and the other tailed beasts are targeted by a powerful antagonist named Toneri Otsutsuki. Toneri plans to capture the tailed beasts and use their chakra to power the "Tenseigan," a doomsday device. Naruto and his friends must work together to stop Toneri's plans and save the world.

Kokuo and the other tailed beasts play a pivotal role in the final battle against Toneri. They combine their powers to assist Naruto in confronting the antagonist and preventing the catastrophic plan from being realized.

The movie highlights the tailed beasts' willingness to cooperate with humans and the significance of their abilities in protecting the ninja world. It also showcases the growth of the relationship between Naruto and the tailed beasts, including Saiken, as they unite to face a common threat.

Kokuo, the Five-Tails, is known for having a quiet and reserved personality. Despite its limited communication, when it does speak, it uses the rather old-fashioned and polite term "watakushi" when referring to itself, which gives it a dignified and polite demeanor. This choice of language adds to its air of formality.

Kokuo takes pride in being a tailed beast and is displeased with being controlled and used as a puppet by Tobi during the Fourth Shinobi World War. This suggests that it values its independence and resents being manipulated. After the war, Kokuo expressed a desire to seclude itself in the forest.

This decision reflects a pacifistic nature, indicating that it no longer wishes to engage in confrontations or conflicts. It seems to prefer a peaceful and solitary existence away from the chaos of the world.

Kokuo has the appearance of a creature that combines elements of a white horse and a dolphin. It has a dolphin-like head with two long, pointed horns and three shorter horns in front (although there are two in the anime). The tips of its horns, hooves, and tails are tan in color, with some tan spots before these areas.

It also has red markings under its dark blue-green eyes. It's worth noting that in the days of the Sage of Six Paths, Kokuo was much smaller and had shorter horns compared to its current size and horn length.

• Control Over Jinchuriki: When the person whom Kokuo is living inside (called a jinchuriki) falls asleep, Isobu can control them. This can be a problem for the jinchuriki, as it might keep them awake at night.

• Chakra Transfer Technique: Kokuo possesses the Chakra Transfer Technique, which allows it to share its chakra with others.

• Tailed Beast Ball: The Tailed Beast Ball is a massive and devastating energy sphere that Kokuo can create. It's a powerful and destructive attack capable of causing significant damage.

• Tailed Beast Full Charge: Kokuo can charge up its immense chakra and then release it with tremendous force, creating powerful shockwaves.

• Tailed Beast Telepathy: With the Tailed Beast Telepathy, Kokuo can communicate with other tailed beasts and individuals over long distances using their minds, which is a crucial ability for coordinating actions and sharing information.

Kokuo has a special power called Boil Release, which is created by mixing water and fire chakra. This power allows Kokuo to heat its chakra to the point of boiling. This forms the foundation for a kind of ninjutsu that uses steam. When Kokuo or its jinchuriki use this power, they become incredibly strong and release lots of steam from their bodies. It's like a super-heated, steamy boost to their physical abilities.

Kokuo possesses a unique ability called "Horn Breaking." This ability allows it to create an incredibly strong and sharp force with its horns, particularly the two long ones. In a battle, these horns can be used to break through tough defenses or even attack enemies with great power.