During his time in the world of the living, Kage was known by the name of Kage Nara. He lived in the age of the shinobi (Naruto Verse). He was a young man hailing from three prominent and powerful clans. The first clan he was a part of was the Nara clan, masters of wielding the yin release to the point of physical manifestation. The second was the Kurama clan, a clan who had mastered the art of genjutsu to the point that their genjutsu could blur the very line between illusion and reality. Those two clans made up half of his bloodline from his mother who was half of both bloodlines. His father was full blood Uchiha making him half decended from Uchiha blood.
Eventually his time came, he was killed during a great shinobi world war and passed over to the afterlife. He had formerly been an anbu and was forced to relinquish emotion and overall gave up any bit of a heart he had possessed. It was a little known fact that some from a certain branch of the Nara clan also possessed dormant shinigami power. In his death, he had possessed the soul and spiritual pressure of a shinigami, but he suffered from a unique condition as well. His absence of heart and emotion during his lifetime had also caused him to begin to hollowfy shortly after arriving in the afterlife.
Unlike most souls, his hollowfication resembled more of a vizored type hollowfication. The cause for this was unknown, but it was halted halfway through as a massive blade plunged through his chest and the forming hollow hole. A kushinata had run him through with a blade and pulled him into hell to atone for the crimes of killing the many he had killed in the name of his village, as well as for his awakening of the mangekyou sharingan which was considered a blasphemy due to it's dark nature and the nature of it's awakening.
He was made a togabito, a sinner who was to live in hell. Due to his odd conditions of transformation, he also retained his shinigami and hollow powers making him a true vizored of natural causes unlike the artificial ones made through hollowfication experimentation. His powers as a togabito, born of the influence and power of hell, were reminiscent of quincies. He possessed full dominance over reishi and could control it willfully. He was able to even envoke the power of creation to some extent allowing him to create constructs from raw reishi. Because of this power, he learned the ability to break down the kushinata and absorb their power as well as the power of the chains of hell and make that power his own. Hell responded by snuffing out his power before it grew strong enough to defy hell. Kage was dragged down to the depths of hell where he could not move nor use his power any more.
Centuries later, an unknown entity was able to pull him from hell and he awoke in the world of the living. He had little memory of his past. He only knew his name, as well as his fighting abilities such as taijutsu. He did not know how to call his sword nor use any of the power of his spiritual body. He also had no memory of his ninjutsu or genjutsu, though in the afterlife he could only use certain techniques as most jutsu were not able to be used unless converted to a form of kido for use with a spiritual body.
Having the uniform and appearance of a shinigami, he was taken in by those patrolling the city at the time to be interrogated as he had no squad number nor was their any information on him. Though Kage would never remember to know, the world of the living he had awaken in was not the same he had died in. He had passed away in the world of the shinobi, yet awoke in a more modern and peaceful city where Karakura town had existed. Somehow, in being pulled from hell, he had jumped through dimensions to a very different timeline where the world of the shinobi never existed, nor did chakra.
He served as a member of the Rukongai for years, dwelling in district 80 Zaraki for quite some time. He eventually developed an interest in becoming a shinigami and made an effort to do just that. He was denied many times because of suspicion. Eventually the suspicion was dropped because Kage had lived there many years without incident aside from fighting to defend himself. They were curious of just how he would turn out seeing as he already had impressive spirit energy, a shihakusho, and a zanpakto. His zanpakto was also rather odd yet impressive, it was jet black with a red cloth wrap for the grip and 3 black magatama for the guard in the pattern of the tomoe seen in the sharingan.
As expected, he passed the academy with flying colors. He was considered a prodigy for having passed the academy in a mere year and a half. He had a natural adeptness for using kido and due to taijutsu training when alive, his hand to hand and swordsmanship was top tier. He was put in the stealth force for some time because of his natural aptitude and he quickly climbed up to the position of forth seat under Kisuke Urahara who was the current third seat at the time.
Eventually, the Kenpachi of squad 11 was replaced with a new Kenpachi from the district 80 Zaraki just as Kage was. This was a major transition as not too long after the captain of squad 12 was promoted to the royal guard. Kage was transferred to squad 11 by request as he wished to fight alongside Kenpachi who he had known from Zaraki and had nothing but respect for the man. Kenpachi was not all too eager to recieve a former stealth force member, but figured that he would at least try the man out and see if he was worth anything. Due to his reputation for being a prodigy and his skill in having moved up to 4th seat of squad 2 then moving to 13th seat of squad 11 after transfering, he caught the attention of the 4 great noble families. There was also the matter he did not belong to a family just as many others in the Soul Society who had to form families, his circumstances were very different though. All of this in mind, the Shiba clan took him in and made him a part of their ranks. This came with it's perks but also further responsibility. Kage took up the offer and saw it as an opportunity to really become someone important to the Soul Society, he could always feel an inner sense of duty to remain strong and do his best to always improve the circumstances of those who relied on his power.
He was soon to be moved up to 6th seat of squad 11, but first he was commanded to carry out a really important mission to prove he is worthy of such a position. A hoard of hollows had been drawn to the world of the living for unknown reasons and he was ordered to dispatch all of them with a small group of lower squad members. According to data, there were no exceptionally strong hollows so it was supposed to be a pretty clear cut mission. It was not going to be that in any sense of the phrase in the end.
The mission seemed to be going well but as they drew close to the completion of the mission, an adjuchas appeared and attacked. It was not something to be expected and the reason for it's appearance was not known. It killed off the members serving under Kage and seriously injured Kage with it's massive claws. Oddly it was trying to devour him but Kage refused to let it have a single bite.
The adjuchas had been called out by the dormant hollow side of Kage. It felt as if there was an adjuchas in the world of the living to be devoured so that the one devouring may become a vasto lordes. Kage fought back with all he had and managed to injure the hollow to the point it tried to flee, in Kage's pursuit he wound up in Hueco Muendo with the creature in the menos forest.
Life in the menos forest was a constant battle, adjuchas sent the gillian after Kage every time and tried to kill him many times themselves. He faced endless war and after 50 years found another who shared in his misfortune.
He had become stuck in the world of the hollows around the time of Aizen's hollowfication experiments. Just after the death of Ichigo's mother, Kage had discovered during his fighting that he possessed the ability to use sonido and cero which were the powers of hollow and arrancar. It bothered him as he knew he could never return to the Soul Society having possessed the powers of a hollow. Surely he would be locked deep within the central 46's prisons for some alleged crime of using forbidden abilities.
3 years following, he finally achieved freedom from the constant war. It really did not matter because he had made himself a home in the sands on top of the menos forest. It was in a little known part of the realm which provided him more than enough protection and the awakening of some of his hollow powers confused any hollows who tried to attack him as they mistook him for an arrancar and retreated. His freedom was earned when he learned how to open a garganta of his own after witnessing many hollows and arrancar doing it.
Now he travels between the world of the living and Hueco Muendo, still too ashamed of his hollow side to return to the Soul Society. He did manage to awaken his Shikai but knows not yet how to wield his bankai.
To get by and continue on a sort of purposeful existence, Kage frequently visits Kisuke Urahara who is more than willing to assist him as well as keep his secret. Kisuke is known to use him as a sort of guinea pig for various devices he is testing due to Kage's unique circumstances. Kisuke also assists in Kage's further training alongside a mysterious acquaintance from Hueco Muendo who has been around for some time but has yet to appear before anyone outside of Hueco Muendo.
Sharingan: Kage retains his sharingan and mangekyou sharingan but he cannot willfully activate either as he fails to remember that he even possessed the ability. Typically it only appears when he is in dire straits, and even then it activates at no more than 20% of it's full potential due to not willfully or skillfully being used.
Kyumin Yami Magatama: (literally - Dormant Dark Magatama), Kage's Zanpakto goes by this name. His zanpakto possesses this name prior to entering it's shikai state. This zanpakto is one of the few to possess a unique name in it's unreleased state. Calling it's name will allow Kage to use it's ability which is again not typical for a sealed zanpakto. The blade is able to condense reishi into it's blade to increase it's force, momentum, and speed. Essentially it can accelerate it's speed to three times Kage's normal speed and can possess the physical force of a blade 7 times it's own size and weight. It is unique to be able to accomplish this but in lightly bending the laws of physics, it burns through alot of spiritual power. Increasing the speed is much easier as it is allowed without bending the laws of physics. The blade is razor thin, yet as sturdy as an extremely dense blade. It's size and light weight make it exceedingly fast naturally and an increase in power through condensing spirit energy will very easily amp up the speed. It takes more power to raise the force and momentum as the blade is essentially very light. It uses dense spirit energy to increase it's force despite it's small thin size. The reason for this blade's unique traits in it's sealed state is due to the togabito abilities and power Kage possesses.
Yami Magatama Kugeki: (literally - Dark Magatama of the Void), Kage's zanpakto in it's released state or shikai state. The blade has a very different appearance and is physically larger mostly in terms of girth. It is shaped differently and weights a bit more than it's sealed state. Despite the increase in size and weight, it is still nearly just as fast as before and more efficiently channels and regulates reishi to boost it's speed constantly as well as it's force. It bears an aerodynamic shape as well which assists with speed while the blade's sharpness is more than that of the sealed state despite appearances stating that it should be the other way around. This blade's shikai state is deceptive, it hits harder, is stronger, is faster, and is overall more powerful than it appears. It possessed the speed of a blade 5 times smaller and 5 times lighter and the strength of a sword far more massive than itself. These are not it's special techniques but they are a part of it's released state. The blade's special technique is it's ability to create and use shadow reishi blades. It's first technique allows it to create quite a few after images with each movement. The after images are offset roughly an inch extended from the previous one starting with the blade itself. The after images possess physical form and cut just as the main blade does. It is effective for offense and defense as if one were to swing the blade around them in the path of an oncoming attack, the shadow blades would make for a powerful countering wall. In attacking, the foe would need to be able to counter anywhere from 10 to a few hundred swords hitting them all at once with just a single swing from Kage's zanpakto depending on how much power was put into the attack. All the while, with every shadow blade blocked in that thrust the next blade will be on inch closer to the body of the foe even if it is blocked. If a cut hits directly, then one swing would yield many cuts with each cut getting deeper and deeper. The second ability of the zanpakto is that it can create a barrage of 2 ft. long projectile blades in a crescent or half circle shape out front of where the blade is swung and launch them. This second attack is identical to suzumushi's shikai attack (kaname tousen's sword.) The third and final attack of the shikai state, as well as it's most dangerous, is known as the shadow shuriken fog. The blade must be swung between the wielder's line of sight of a shadow and the shadow. The shadow can be of anything so long as it is some form of shadow or darkness. When swung, the blade casts reishi through the shadow at range which creates anywhere from tens to hundreds of small yet sharp shuriken made of reishi combined with the shadow to give them physical form. The blades can be controlled like senbonzakura but additionally can be controlled with the sword as well as the hands. While they can be freely controlled, their finishing strike involves them surrounding the target on all sides and then swirling into a cyclone which moves at excessive speed then enclosing on the foe who is unable to escape thus cutting and grinding them into blood and dust. They enclose continuously until they grind against eachother and literally grind themselves into dust as well and return to shadow. The blade's major downside is the rate that it burns through spritual power and reishi. Kage can only use it effectively for a limited amount of time. There's also the risk of cutting things unintentionally as the blademoves at very high speeds and all attacks possessed by it are both fast and focus on many multiple strikes. It is definately one of the more powerful zanpakto, but with it's power comes greater risks as well.
Demon Wind Shuriken Steele schnider: A weapon unique to Kage. He possesses these weapons in limited quantity due to their size. He can forge new ones with time, and always carries roughly 7 of them on his person. Because of their size, they are stored in special curse tags which highly resemble item sealing scrolls used in the era of the shinobi though they are about half the size of a paper bomb and only seal one item per tag. They are demon wind shuriken, large aerodynamic folding shuriken just like as seen in Naruto. The difference is that the blade edges of these glow red when unfolded, the red glow being a coating of extremely high vibration reishi over the blade edge. Their function is identical to steele schnider, like that which is used by the quincies but is merely a different weapon and plays on Kage's togabito power which is identicle to the power of the quincies but is more powerful and fine tuned. They can even land in a pentagram pattern to envoke sprenger with their own ginto. Kage developed them based off of the quinie's weapons but wanted a more familiar weapon.
Kunai, shuriken, senbon: Kage possessed a limited number of each of these weapons kept in seal tags for storage. They function just like that of quincy arrows and so they do not purify hollows but instead kill them all together. Unlike quincy arrows, these weapons are all made out of physical materials and are charged with reishi thus making him supply limited as well as leaving evidence in physical form of their usage.
Complete Reishi Dominance: Though usually regulated, Kage can master complete dominance over reishi like that of the letzt stil. Just as with any great power, Kage normally has to regulate it to prevent suffering from harmful side effects. It would seem that the stronger togabito form of the quincie's power would be greater than that of even the quincies themselves, but there is a drawback. The reishi is usually pulled in and controlled at twice the speed voluntarily and is not as pleasant to it's controller. It's pulled in and harnessed like a violent current which harms Kage as he does it. Kage can possess immense power with this ability but the more he uses it the more it harms him when the current dies down.
Control over his hell chains: The unbreakable chains of hell are still embedded into him though severed from hell itself. He can use these chains as a physical weapon as they are difficult to break and usually invisible unless physically interacted with. If one was to allow him to connect the hell's chain to the chain of fate on another, he could absorb the soul and convert them into reishi thus 'killing' the soul though this task requires a stationary target or at least semi stationary.
Ransotengai: The advanced art though to only be present in quincy geniuses. Due to Kage's similarities in terms of abilities, he too has mastered the ransotengai. It's mastery took quite alot of time and effort and explains why Kage has yet to attain bankai.
Taijutsu & Bukijutsu: Due to Kage's history as an elite shinobi, he possesses highly advanced taijutsu and skill with weapons of many sorts. His muscle memory and instincts have retained all of his training despite his amnesia.
Cero: Kage possesses the unique ability to use cero like that of a hollow. His cero is a vibrant red like most common ceros but his possesses rather potent power and speed in comparison to a normal cero.
Muchos Cero: A multiple cero technique. Kage is able to focus his spiritual power in the air directly around him and thus form floating ceros. Normally they form in an arched pattern just behind him (roughly the same location as truth seeker orbs in Naruto, only a bit further to the sides to prevent the cero from hitting too close to it's user). This keeps his hands free and permits him to create more ceros than he normally could. Usually they are of divided power as Kage has yet to master usage of cero. 5 at a time is the absolute maximum Kage can manage but normally 3 is the best he can do in the heat of battle.
Flash step: A high speed movement technique used by soul reapers. The technique essentially allows one to teleport in the eyes of those unable to use it. Those able to use flash step, or similar moves, would be able to keep up and see the movements. Those unable to use the technique would not even know what hit them. In most cases, this technique will allow a shinigami to draw their sword, make multiple strikes, resheathe their sword, and then find a place to stand and look back and a foe unable to keep up would not have even that the person had moved until moments later.
Sonido: The hollow and arrancar equivalent to flash step. The only differences are the unique bass like noise that is made when it is used and that it may or may not be slightly faster than flash step.
Two step vanishing: Kage is a unique individual in possession of flash step and sonido. Normally using one of these techniques requires a brief cooldown depending on the user. It could require a fraction of a second or a full moment to cool down from one technique or the other. Sonido and flash step operate on different principles and thus Kage figured out that he can use them simultaneously to essentially outspeed an extremely advanced flash step by just under 2 times the speed and distance while not needing to cool down from it at all for twice the duration. Essentially he can cover twice the ground at twice the speed using this technique. The drawback is that the cooldown for using this technique is longer once you hit cooldown and it exhausts stamina 3 times as fast as flash step. Kage only uses it strategically.