Basic Information
Full Name: Kaien Uchiha
Gender: Male
Birthday: December 11
Age: 11 - 13 (Part I), 19 - 20 (Part II), 25 - 26 (Part III), 36 (Part IV)
Current Residence: Hidden Ash Village
Affilation: Konohagakure (Former), Uchiha Clan, Senju Clan, Mercanary Organisation (Former), Akatsuki (Former), Reborn Uchiha Clan (Currently)
Occupation: Clan Leader
Konoha Rank: Jonin
Teachers: Sakumo Hatake, Madara Uchiha
Students: Kakashi Hatake (Brieftly), Itachi Uchiha, Shisui Uchiha, Unknown Female
Family: Kisuke Uchiha (Father, Deceased), Misaka Uchiha (Mother, Deceased), Kayden Uchiha (Brother, Deceased), Obito Uchiha (Brother, Deceased)
Ash Village Rank: Kage
Elemental Type

Fire Release

Wind Release

Earth Release

Lightning Release

Water Release
Kekkei Genkei

Sharingan

Mangekyo Sharingan

Wood Release

Boil Release

Lava Release

Blaze Release
Background
Twenty Six years before the Nine Tailed Fox attacked the village of Konoha, on December the 11th Kaien was born into the Uchiha Clan to Kisuke Uchiha and Misaka Senju (Uchiha). A year later they would give birth to another child, Kaien's brother, Kayden Uchiha.
Kaien grew up in konoha and at an early age he gained a passion to become a ninja. Over the years he would learn basic jutsu, discover his first elemental affinity of fire due to his Uchiha blood and befriend a girl named Kayla.
At the age of five Kaien enrolled in the Konoha Ninja Academy with Kayla, it was here his potential was recognised, Kaien excelled at all of his lessons and managed to graduate the academy at the age of Eleven with the title “Number one Rookie”.
After graduating and becoming a Genin, Kaien was put into a squad with Kayla and another student named Zeeke. They would then discover their Jonin teacher to be Sakumo Hatake, Konoha’s White Fang. Soon after Kaien's third brother would be born, Obito.
Personality
Since his Childhood Kaien was a Nice, Polite and respectful boy, he looked out for his friends, loved his family and respected his elders. Due to his talent and power he was slightly cocky. When he became a Genin he would be taught and shown that working together would always be more effective than relying on only himself, he opened up to people more.
Kaien had always been intelligent and as he got older he would become wiser. In combat he would be able to think up effective strategies and plans very quickly. He became close friends with his squad during his childhood, Zeeke became his best friend where as with Kayla it seemed Kaien had grown romantic feelings.
After the death of his friends and returning after five years of being missing, it seems Kaiens personality had changed completly, the kind compassionate and peaceful person had changed to a violent, cold silent killer. He mostly kept to himself and only really spoke when he was spoken too, Tobi manipulated him to do what he was told by promises for information on the incident.
During the Nine Tail Fox attack on Konoha, Kaien would accidently murder his brother , after this incident Kaien suddenly realised what he had done, In grief and sorrow all of the things he had done the past few years came rushing back to haunt him, he swore to his brother that he would redeem himself, after losing to Madara in battle Kaien went into exile and vanished for another ten years.
When he would finnaly return it seemed that Kaien had reverted back to his former personality, caring for his people and friends.
Appearance
Kaien like all of his clan had black eyes and dark hair, his hair was spiked up and tied into a ponytail at the back. During his younger days, Kaien would wear a black outfit with a long collar, on the back of the shirt would be the Uchiha Clan crest. When he got older he would wear his own customised Konoha Jonin outfit.
When he joined the organisation he wore various different outfits, but all of them he would wear a long coat, he often wore a set of black plated armour decorated with Sharingan seals. in the last few days he would gain his akatsuki cloak, it is not known what he wore under it.
After returning from Exile, Kaien looked pretty much the same but slightly older, he wore a black traditional japanese outfit when he was in the village but during missions he would wear his old Black plated armour with a long black coat, on the back of the coat is the uchiha crest with a dragon wrapped around it.
Kaiens main appearances can be seen below.
Part I

Appearance in Part I
Part II

Frontal Appearance in Part II

Back Appearance in Part II
Part III

Armour used in Part III
Part IV

Frontal Kage Outfit of part IV

Back Kage Outfit of Part IV

Frontal Sharingan Armour used in Part IV

Back Sharingan Armour used in Part IV
Abilities
Kaien has been stated to be one of the most talented and strongest members of the Uchiha Clan, Even at a young age he held a great amount of potential and chakra, easily able to learn elemental jutsu's at a young age. The only people suggested to be stronger than Kaien in the clan was Madara and his brother Izune.
It is also obvious that Kaien has a incredible amount of chakra, It is hinted that his incredible potential and power comes from being a direct decendent of both the Uchiha and Senju Clan, utilizing both of the strongest bloodlines in the ninja world.
Combat Skill
Kaien excels at both Ninjutsu and Genjutsu, he has learned and copied hundereds of different jutsu's over the years. Kaiens Taijutsu, though not as powerful as his ninjutsu and genjutsu is still very effective, the main result of his taijutsu is his incredible speed, able to move faster than the normal eye can follow, Kaien mainly fights with his Katana, using his speed and agility he combines that with various jutsus to create a powerful unique fighting style.
Summoning Technique

Kaien's drake Summon
During his dissapearance it is revealed that Kaien has made a contract with Dragons, He has been

Lord Obsidian, King of the Black Dragons
shown to be able to summon a black drake which allows him to fly, the drake can also use various fire / Lava techniques.
Kaien has been seen to use his sharingan to syncronise himself with his summon, to allow them to move and fight together more effectively, Kaien also combines his elemental attacks with his summons to make even more powerful attacks. After his exile it would be revealed that Kaien has gaine the ability to summon the King of the Black dragons Lord Obsidian.
Elemental Techniques
Posessing incredible talent and power, Kaien has managed to gain all five elemental affinities over the years making him a truly powerful individual. At a young age he developed his fire affinity, learning the clans rites of passage jutsu at five years old. During his time as a Genin Kaien unlocked his second affinity of wind which he trained with over the years, combining his wind element he could make his fire attacks twice as powerful.
As a Chuunin it would reveal that Kaien learnt his third affinity of Earth, he found it more difficult to learn this element but after several years of mastering and becoming a Jonin he would learn how to combine both his fire and earth elements into Lava release, his first elemental kekkei genkai. After Kaine went missing for five years, he returned in the organisation demonstrating that he mastered the Lava release during the time.
During his time in exile, Kaien would learn the truth of his mother and his family heritage from her, and eventually gaining the wood release, even to this day he finds it hard to control this kekkei genkai due to only half of his blood being Senju, also during this time Kaien learnt the elements of Lightning and Water, also gaining a second elemental Kekkei genkai the Boil Release. It is also revealed that sometime years before, Kaien learnt how to manipulate and shape the flames of Amaterasu, giving him acess to the Blaze Relase.
Sharingan

Kaien's Sharingan
As a member of the Uchiha clan, Kaien possesses the Sharingan
, the clan's Kekkei Genkei. Kaien awakened his Sharingan during one of his first missions as a Genin. Over the years Kaien has extensively trained with his sharingan, he is capable of constantly using the sharingan without any noticable energy drain, he also has the ability to overcome the genjutsu Tsukuyomi as well as any other genjutsu easily.
Apart from these features his sharingan posseses the normal abilities of being able to copy, remember and recreate moves and jutsus performed by enemies, the ability to see a persons chakra flow, as well as the ability to follow fast movements and brand a special form of hypnosis where the user seems to be able to predict the enemies movements.
Mangekyō Sharingan

Kaien's Mangekyo Sharingan
Kaien awakened his Mangekyo Sharingan after the death of the girl he loved, Kayla. His Mangekyo Sharingan takes the form of a black three point pin wheel design on a red background.
Kaien first unlocked the genjutsu ability of Tskuyomi, the ability to trap an enemy in a different dimension where they can be mentally tortured, Kaiens mastered form allows him to be able to control the enemies perception of time within the genjutsu.
Kaien would soon after unleash his second ability, Amaterasu. This ability summons the jet-black flames of the Amaterasu, said to be as hot as the sun, ignite at the focus of the user's vision. They're unavoidable as long as the user keeps their eyes focused on their target. The flames are extremely powerful, capable of burning through anything and can even smother regular flames easily. Amaterasu is said to burn for seven days and seven nights, and cannot be extinguished with water or any other normal methods. However, the flames burn fairly slowly, allowing anyone struck by Amaterasu an opportunity to remove whatever clothing or body parts have been caught ablaze. Kaien has shown to have mastered the ability, able to control, move and shape the flames to his will, he has also been shown to be able to put out the black flames. Though the ability still strained his eyes and worsened his eyesight.
Kaien then learnt the next ability named Kamui, this ability allowed him to cause an area of space to collapse on itself, sending anything in the area to another

Kaien's Fully formed Susanoo
dimension, this ability can easily rip limbs of if caught in the space collpasing. This jutsu takes a lot of chakra and energy to use but doesnt cause much strain on the eyes.
Kaien's final ability would be Susanoo, this ability to manifest a giant spirit, the user becomes a medium for summoning the spirit. Kaien has mastered this ability, able to fully summon his susanoo's complete form as well as partially summoning body parts of the spirit, the spirit can be controlled completly mentally. This ability causes a lot of strain in both eyes and damages the users vision. Kaien's Susanoo is green in colour and wields a long halberd like weapon in one hand and a large shield in the other.
Kaien eventually became blind in one eye due to over use of abilities.
Eternal Mangekyō Sharingan

Kaien's Eternal Mangekyo Sharingan
After the death of his brother, Kaien implanted and fused Kayden's eyes with his own, granting him the Eternal Mangekyo Sharingan, this new form of the sharingan granted lots of new abilities as well as improved old ones. With these new eyes Kaien could use all four previous techniques without strain on his eyes and without fear of going blind.
The first new ability was Amatsu-Mikaboshi, this is a powerful genjutsu which traps the enemy in an illusion with their worse nightmare, they wont be able to leave unless they overcome and defeat their manifested fear or they resist the ability with a mangekyo sharingan.
The second ability was Raijin, this ability blasted out a powerful storm of violet lightning from the user's eye. The third ability Fujin caused a whirlwind of razor sharp winds to form around an enemy, slicing and shredding up whatever is trapped within it. The Fourth ability Ryujin forms a large orb of heavy flowing water around the user, able to stop most jutsu.
All four of these abilities cost quite a lot of energy and chakra to use, reckless use would exhaust the user.
The final two abilities were Izanagi and Izanami, Izanagi was the most powerful genjutsu and a forbidden technique, this ability allowed the user to cast a genjutsu which would distort reality, causing anything that happened during the time to just vanish like it never happened, this ability has the power of even cheating death. After use of this jutsu, the eye using it will forever become blind, even if it is an eternal mangekyo sharingan. Izanami is a powerful space time jutsu which allows the user to distort their own body, allowing them to phase through attacks and objects as well as allowing the user to reform their body anywhere (teleportation)
Eternal Mangekyo Rinnegan

The Eternal Mangekyo Rinnegan
To escape death in his battle against Madara, Kaien had to sacrifice his right eye, using the forbidden technique Izanagi, faking his death and causing eternal blindness in his right eye. After sucessfully tricking madara into thinking he was dead, Kaien tried many times to inplant different sharingans into his right eye to recover his blindness to no sucess. Years into his exile and after becoming the Kage of his Ash village, he reunited with Konan, discovering that Nagato had passed away, Learning of his blindness, Konan suggested trying to inplant Nagatos rinnegan into his right eye, the surgery seemed to be successful, and Kaien unlocked a new dojutsu, a fusion of the Eternal Mangekyo Sharingan and the Rinnegan.
The new dojutsu surprisingly gave Kaien a gigantic increase in power and chakra, but due to not having the blood of nagato, the dojutsu would cause immense strain on the body, though it would not cause blindness, the body would quickly exhaust. The dojutsu would activate upon focusing on something, due to this a lot of the time Kaien wore an Eyepatch over his right eye. Once activated Kaien would be able to fight for ten minutes before the drain would exhaust all his chakra and energy.
With this eye Kaien is able to use all his previous abilities, But along with his former he has managed to gain a few of Nagato's unique abilities, He has managed to obtain most of the Deva paths abilities, Shira Tensei and Chibaku tensei, the other ability he has shown to retain is the Preta paths ability of absorbing most attacks though it is shown using up a lot of energy when used by Kaien.
It is also possible that Kaien has other abilities that Nagato had but none others have been shown yet. Implanting the Rinnegan has also shown to grant Kaien the ability to gain Water and Lightning elemental affinity, the two elements Kaien seemed to not be able to gain before.
Part I
Mission to the River Country Arc
After graduating and being tested by Sakumo, the group passed the test and hence Team 2 also known as Team Sakumo was born. Their first mission was a simple D rank one in the River Country, A farmer requested help around his farm. The mission was mainly a chance for the team to bond and train, during the day the group

Kaien during Part I
would help around the farm, and during the nights they would train in controling chakra, ninjutsu and spar.
Kaien and Zeeke became good friends and were like rivals, Kaien then started to notice Kayla more, starting to like her in a romantic way. During the third night, a large band of Bandits attacked the farm, trying to steal crops and supplies, The group fought together to protect the farm but due to not having any real combat experience the three Genin were close to doing nothing while Sakumo fought the group of over six bandits.
One of the bandits broke past Sakumo and attacked Kayla, who froze in fear. Kaien's Sharingan then awoke, giving him an increase in strength and speed allowing him to easily subdue the bandit before any harm could be done.
After the mission the group returned to the village and worked harder to become stronger. During the next year the group would come to complete over twenty D rank mission and three C rank missions. Kaien would also gain all three tomoe of his Sharingan.
Chuunin Exam Arc
After a year of doing missions and gaining experience, it was time for the Chuunin exams, Sakumo accepted the three were ready for the exam and wished them luck. In the first round of the exam, a written test which tested the ability to gain information, Kaien gained the answers for the test by using his sharingan to copy the pencil movements of the people around him. After successfully answering the tenth question, all three members of the team made it into the second round of the exams.
In the second phase, Team Sakumo were sent to the forest of death, here they were given a scroll and were tasked to gain another scroll of a different colour and rendevous in a location in the center of the forest. The group soon encountered another group from a different village, Kaien was trapped within a Genjutsu while the three ninja ganged up on Zeeke and Kayla, Kayla then remembered how to break a genjutsu using the technique Genjutsu Release, she applied a sudden surge of chakra through Kaiens body breaking the genjutsu.
Zeeke then revealed he had an elemental affinity of wind, the three started to gain an advantage in the fight, fighting evenly with the other ninja, it wasnt until Kayla reminded the two that fire attacks are increased by wind elements, Kaien and Zeeke then combined their elements to create a devastating attack which defeated all three of the ninja in one attack. They then found that the scroll they needed and proceeded to the rendevous building and gaining access to the third phase of the exam.
The final phase of the exam consisted of a tournament system for the remaining ninja to fight against each other. In the first round Kaien was against a rather weak ninja, Using his sharingan he could follow and predict the movements of his foe and easily countered all the attacks, The enemy ninja would then use a taijutsu technique, a powerful uppercut, Kaien copied the move with his sharingan and countered it, before launching the same attack back at its user, defeating him.
In the semi finals Kaien fought against a Taijutsu expert, the enemy ninja moved at an incredible speed and even kaien found it difficult to keep up and defend himself, after having most of his attacks miss and countered kaien had to think up a plan, he created two shadowclones before slyly sticking an explosive tag onto the back of one of the clones, he then sent the two clones to attack the foe and hoped he fell for the trick, which he did, countering and attacking the clones caused the tags to explode point blank, rendering him unconcious and unable to fight.
In the finals Kaien fought against a powerful ninja of the Kaguya Clan which had the kekkei genkai Shikotsumyaku, the ability to completly manipulate their skeleton and bones, instantly regenerating any broken or removed bones. Kaien fought agressively against the enemy but everything he seemed to do seemed to be pointless, he managed to break the enemies arm and leg but the bones instantly regenerated. The enemy then formed large blade like bones out of the wrist and proceeded to attack kaien in a barrage of attacks, Kaien defended with his katana and held his own, counter attacking the foe.
The two seemed to fight evenly though no damage could be done to the Kaguya member, while Kaien was exhausting himself. Kaien attemped the trap his foe in a genjutsu but the Kaguya member easily broke out of it by using his bones to cause pain which overided the illusion. Kaien then used the last remaing energy he had to throw two kunai at the foe, who dodged them, little did he realise they had wire tied to them, Kaien then used a fire jutsu to ignite the wire, causing a large fiery explosion before passing out. His last attack managed to wound his foe rather badly but he lost the match.
In the end Kaien, Kayla, Zeeke and various other Ninja were promoted to Chuunins.
Elemental Training Arc
After becoming a Chuunin, Kaien underwent intense training to completly master his fire affinity, He also discovered his second affinity of wind during this time and trained towards improving it. Also around this time the squad would undergo more missions, completing several C and B ranked missions. He also spent a lot of time with his family, training a lot with his two younger brothers. This would carry on for another four years.
Part II
Skirmish with the Hidden Sand Arc

Kaien during Part II
Six years after the chuunin exams Kaien is now a Jonin and has his own squad of Genins, one of which is another prodigy of the Uchiha Clan, Itachi Uchiha. During this time the Third Hokage gave a dangerous S ranking mission to Sakumo, asking he chose people for his squad. Sakumo would choose a vareity of the top ninja in the village as well as his former students Kaien, Kayla and Zeeke.
The mission was to eliminate a small group of sand ninjas who were plotting to infiltrate konoha and assassinate the hokage. And capture a certain member of the group named Kazuya.
During the mission the group split into two, Sakumo lead half of the group and Kaien lead the rest with Zeeke and Kayla, when they found Kazuya he managed to evade capture and started to flee. Sakumos group chased after Kazuya while Kaiens fought the rest of the ninja. After being seperated Sakumos group was ambushed, all members of his squad were killed in the ambush, Sakumo managed to defeat the ambushing ninja and proceeded to chase Kazuya, it was then that Kazuya revealed that their was an ambush three times bigger than the one he had just been caught in approaching the other group.
Sakumo decided to abandon the mission to try save his comrades, On Kaiens side of things the group were heavily outnumbered and surrounded, only half of the squad were left alive and they were struggling to fight off the attackers. Sakumo finally arrived just in time and saved the group, with his extra support the group managed to escape with no more casualties.
After returning to the village failing the mission, everyone minus Kaien and Kayla shunned Sakumo for abandoning the mission, even the people he saved and even

Sakumo having his last conversation with his students before he would take his own life.
his own student Zeeke shunned him. Sakumo fell into depression and the quality of his work dropped incredibly. Sakumo spent a day with Kaien and Kayla, reminicing of the past, he questioned if he had done the wrong thing and if he was a bad ninja and person, Kaien reasurred him he had done the right thing, cheering him up a bit, at the end of the day they sat under the moonlight having a drink together, Before the two would leave and go home Sakumo told them to remember this phrase, a phrase he had taught them before and constantly told them during their time as Team Sakumo "Ninja who abandon the mission are scum, But Ninja who abandon their friends are worse than scum." Several hours after the two went home, Sakumo took his own life.
After the funeral of their teacher the relationship between Kaien and Zeeke got rocky, they started to have conflicting views on what had happened and who was to blame for the death of their teacher.
Betryal Arc
During the next few weeks, Kaien and Kayla continoued to Grieve, In Sakumo's will it requested that Kaien took care of his Son Kakashi and train him, Kaien could not accept the offer due to not being in a state of being able to be a good teacher, he asked a fellow friend and fellow Jonin Minato Namikaze to train Kakashi instead of him, Minato would also take on Kaiens youngest brother Obito around this time. Around this time Zeeke joined the Anbu group Root, working under Danzo.
Several months later rumors had been brewing that a war was on the horizon, Kaien and Kayla were requested to form a squad and investigate these rumours. on a secret mission from the third hokage. Investigating the land of rain, Before he would leave on this mission Kaien hung out with his two brothers, he told them both to remember a saying his teacher Sakumo had taught him "Ninja who abandon the mission are scum, But those who abandon their friends are worse than scum"

The results of the ambush
During this mission the group would uncover a conspiracy, Danzo and root were secretly in an alliance with Hanzo of the hidden Rain village, Danzo would help hanzo in the future if Hanzo helped Danzo become the Hokage. The two planned to create a war where Danzo would show he had what it took to become the hokage, stopping the war himself with root.
Root discovered the investigating group and ambushed them in the night. The whole squad were quickly wiped out, Kayla was caught in an explosion and was dying, Kaien confessed his love to her, telling her she couldnt die yet, that he needed her. Kayla smiled and
kissed Kaien, telling him that she loved him too, after that she seemed to die. Kaien fell into despair,

Kaien ripping a summon to pieces with his bare hands in his rage
his head felt heavy, his whole body felt strained, his heart and eyes burned, Kaien's Mangekyo Sharingan was awoken. His left eye bled as he felt an excruciating pain, He felt like his heart was being ripped to pieces, black

Kaien's Mangekyo Sharingan awakens
flames formed around, dancing around the root ninja, incinirating them, the flames of Amaterasu. Kaien proceeded to go into a rampage, slaughtering the root and amagekure ninja that stood between him and Danzo and Zeeke, Kaien even managed to rip apart a summon with his bare hands in his state of rage. Moment later before reaching his goal and due to sheer exhaustion, trauma and overuse of the Mangekyo Kaien passed out. The last thing he saw was Hanzo, Danzo and Zeeke stood atop a cliff.
Kaien eventually woke up to find himself in a bed, bandaged up, A man greeted him with shoulder length messy hair, he wore a mask

The man named Tobi introduces himself.
which covered everything but his

Danzo, Hanzo and Zeeke appear to the group
right eye. He introduced himself as Tobi, He told Kaien that nobody survived except for him, Kayla had died and confirmed the people responsible was Danzo of Konoha, Hanzo of Amegakure and Zeeke of Root. He promised Kaien the chance to get strong enough to defeat them all and avenge the one he loved, the chances he would need to kill them and information reguarding the incident, all for the price of joining his organsiation and helping him with various missions.
Kaien agreed to join, and would never be seen or heard from again for another five years.
Part III
Recruiting Kakazu Arc

Kaien removes his mask at the organisation meeting, revealing his Sharingan
Five years later lots of Anbu and Root Ninja were reported to go missing in Konoha, In an unknown forest location a masked man stood among various bodies of konoha Anbu. The man proceeded to enter a secret cave, here he met Tobi and Three other men. The masked man removes the mask revealing himself to be Kaien. He had now over the years earned the Nickname of "Kaien of the Demonic eyes."
During the meeting the un named member insults Kaien and taunts him, eventually leading Kaien to snap, activating his Mangekyo

Kaien angered reveals his Mangekyo
Sharingan, trapping the man in a horrifying illusion, another member named Zetsu laughed at the man screaming. After a while Tobi breaks up the fight, It is then revealed that the organisation will finally be moving to phase one of their plan, to recruit more members for their organisation. Kaien and another member named Sesshou were assigned to track down and persuade a man named Kakazu who was rumored to be immortal to join the organisation.
Before leaving, each member was given a ring, as proof of being a member, Kaien recieved the Shu ring, which was red.
Secretly Tobi suspected Kaien of not being completly loyal to the organisation, and requested Sesshou to keep an eye on him, sending casual reports of his actions and any suspicious activities. During the mission the two got on rather well compared to other teams, They eventually tracked down the man named Kakazu who was collecting a bounty, they tried to talk to him but he refused to listen to them unless they proved their worth.

Kakazu meets Kaien and Sesshou
Sesshou and Kaien fought Kakazu together, working incredibly well with one and another. Combining their strength and jutsu's they managed to impale Kakazu through the heart, Though this proved pointless as it was proved Kakazu was indeed immortal. Kakazu impressed by the skill agreed to listen to their proposition, Sesshou finally managed to pusuade him to join by mentioning the chance to make lots of easy money and easily becoming rich.
They then told Kakazu that the leader would contanct him when they were ready to give him his initiation, The three men then parted ways, Sesshou and Kaien soon met up with Tobi, their they were congratulated and praised for their first mission being accomplished.
Amegakure Arc

Nagato meets Kaien of the Demonic Eyes
A few weeks after recruiting Kakazu, Kaien was given another mission by Tobi, Rumours of a powerful gang existed in Amegakure, lead by a man named Yahiko and his two comrades Nagato and Konan. Tobi wished for Kaien to befriend them and form an alliance between the two groups. Tobi also informed Kaien that their would be a strong possibility of encountering Hanzo and root members, a chance for him to have his revenge.
It wasn't long after Kaien arrived in Amegakure that he met Nagato of the Amegakure Trio, the two men chatted and discovered a common interest, the two held a deep hatred for Hanzo of the Salamander, Nagato had heared rumors of a powerful ninja named Kaien of the demonic eyes, he was keen for them both to help each other to complete their common goal. He agreed that the two groups should form an alliance. Shortly after this Nagato took Kaien to a secret location, introducing Kaien to Yahiko and Konan. The three quickly befriended Kaien and tested him to see if they could trust him and if he was a strong as rumors had said., The four of

Kaien gains the trio's trust, fighting with nagato against Hanzo's men
them did a few missions together during the next few days, fighting lots of Hanzo's men. After gaining the trust of the trio, they would take Kaien to their base and introduce him to their gang, it was here that Kaien met someone he didnt expect to ever see again, Kayla.

The Amegakure Trio and Gang, With Kayla to the most left behind Konan
It was then discovered Tobi lied, Kayla had never died, she was rescued by the Amegakure trio, she found out that nobody else had survived, She joined the gang, to join the fight against Hanzo, wishing to avenge her thought to be deceased lover, over the next five years she would slowly grieve and get over the death of Kaien. Kaien was pissed off at Tobi, this would eventually lead to Kaien's defection.
For now he was in utter shock at Kayla being alive, the two had a sweet reunion, confessing their love to each other once more, they could finally be together for ever. Months would pass as Kaien and Kayla fought with the trio against Hanzo. Half a year later during the third great ninja war, the group recieved an intel, Danzo and roots general Zeeke were sighted in Amegakure, at the same time Hanzo requested a meeting with Yahiko discussing peace. Kaien wished to join them but they insisted that he followed the lead on Zeeke.
In the end Kaien followed the lead on Zeeke, after a day of investigating Kaien tracked him to a location a mile away from the village, the two fought an intence battle, Kaien was forced to use his Mangekyo Sharingan, unveling a technique he had never before had to use in a battle before, Susanoo.

Kaien using his fully formed Susanoo against Zeeke.
Even with his new trick, Kaien still could not overpower Zeeke, It seemed he too had gained incredible strength over the years. developing his own kekkei genkai of dust release. The two still fought amazingly well, Kaien countered the powerful dust release with his lava release and Susanoo attacks. The battle was even until Kaien unveiled a new Kekkei Genkei he had learnt, Blaze Release, the ability to shape and freely manipulate the flames of amaterasu. With this Kaien managed to overpower Zeeke, Killing him in a blaze of black fire.
Not long after, Kaien learnt that the meeting with Hanzo was a trap, Yahiko had died and Nagato was sevearly wounded. He rushed back to base as quickly as he could, even though he bared deep injuries from his fight with Zeeke. Kaien contacted Sesshou, requesting his help due to his incredible medical skills. Sesshou managed to put Nagato into a stable condition as well as implement some of his own technology which he invented. These would be Nagato's support chairs and chakra recievers.

Nagato within Sesshou's Life support system
Kaien was told by Sesshou that Tobi has given him a month before he had to return back to headquaters, bringing Nagato back with him. For the next month, Kaien and Kayla fought in the war against Hanzo with Nagato and his gang, many members of the gang were killed but the group prevailed, Nagato hunted down Hanzo and salughtered him, slaughtering everyone connected to him, he had exacted his revenge.
After the month ended, Tobi eventually made his appearance in Amegakure, by this time Nagato had become the "God" and leader of Amegakure. Nagato now going under the alias Pain agreed to join the organisation as did Konan. But Tobi then revealed a new twist to the group, he wanted Pain to act as the leader of the organisation before the other new members joined. As Tobi himself had other buisness to attend to, and so with this, Pain would soon become the leader of the organisation.
Kazekage and Sasori of the Red Sand Arc
Soon after Kaien returned back to the land of fire. Not long after entering Kaien would recieve a messege from Tobi, requesting he attend a meeting nearby. When he would arrive at the location Kaien met Sesshou again, who seemed to have killed several Konoha ninja. Moments after several newer members of the organisation arrived that Kaien had never met before.