Shun was born to a Kumogakure Uchiha family, as most are nowadays. He was never the brightest, nor the dimmest light in the bunch but he was talented. As a kid he was able to sense chakra signatures and pull off even A-rank Raiton ninjutsu at genin years. His parents saw this and allowed him the secrets to the Mangekyou Sharingan. Shun, later down the road unlocked this ability. He would soon go out for his country and seek out Bocchiere, and end up fighting him to the death. This of course resulted in his death. He trekked the underworld, training to his limits before he found himself alive once more, some time later with the scroll of Rasengan in his possession. Soon after, he left Kumo in favor of the organization known as Boshoku, however his loyalty to Kumo never wavers, and still staying iron strong.
Shun wears a cloak over the rest of his attire. This cloak is lined by extremely strong metals, yet is still flexible, allowing for free movement. Inside the cloak is a normal dark blue uchiha style shirt with the Uchiha crest on the back. He wears normal black shinobi sweats, and shinobi tabi boots. On his torso, one would notice the scars and such all over, including his arms. These are the results of years of training and fighting. On his right shoulder would seem to be a tattoo, although it would actually be the Curse Mark:Astral Seal.
Shun has a weird personality. Sometimes he can be serious, and sometimes he can be the jokester. He holds a deep passion for his friends and family, and cannot tolerate anything wronging them. He would even go as far as to kill if he has to. Deep inside, however is his primal nature that he cannot resist, this being the need to shed blood whenever he fights. No matter what he does or how he does it, he has to shed blood. It's brutality in its most primal form considering he can be compared to a lion when he does. This has occurred after he rose from the grave.
Shun as a young man has mastered Katon, art of the flames being able to utilize the most complicated Katon ninjutsu with ease. His elemental secondary would be the Fuuton, art of the wind. He is by no means a master of this art, but he's adept enough to combine the two and create hotter flames.
He has gained the Eternal Mangekyō Sharingan from his brother Gou. He had went blind during his fight with Bocchiere, and when he came back to life, his eyes were still broken. He had taken Gou's and gained the Eternal, thus allowing him to use his Mangekyō powers at free will without fear of losing his light. From his own power, stemmed Kotoamatsukami, a genjutsu that causes those around him to bend to his will upon eye contact, as well as the Amaterasu, pinnacle of the katon ninjutsu known to man caused by its inextinguishable flames.
Finally, Shun has developed the trait, Shirogane Reiki. It's common knowledge that the body is filled with points called chakra nodes. These chakra nodes allow chakra to pass through, providing the chakra network. Well, inside of the nodes are wasted chakra that adheres inside of them. This wasted chakra is used in the Shirogane Reiki technique to create an aura that has molded into a wind-like state around the user, though still made of pure chakra or other energy used. Shun found this ability during his training to hone chakra control at a young age, capable of manipulating it with ease.
Shun at one point in his life became partial to utilizing genjutsu in order to become well rounded in the art of the shinobi. During so, he came up with a way to cause people to fall under his illusion utilizing a bit of chakra and an object, including a part of his body. When he utilizes an object like a kunai or shuriken, he fills the object with chakra while it is in his grasp, before releasing it. Once released, the chakra reacts to one's vision causing the enemy to fall under an illusion once they looked at the item.
Curse Mark: Astral Seal
Shun was imprinted with this seal since he was but a genin. This seal is Shun's cursed mark. Like most of the other cursed marks in the world, this seal, once activated, floods the user's body with dark chakra, corrupting them slowly, yet increasing Shun's physical prowess and chakra reserves. Shun has to keep this seal in constant check. Otherwise, it'll get the better of him. To do this, he only releases the mark in small portions at a time if needed. If he did release the full seal, he would know that the fight would have to end soon, otherwise he would enter phase two. Stage two is a double edged sword. Shun basically transforms. His feet and hands become clawed, his hair grows longer, his teeth grow sharper, his skin darkens, covered with fur, and wing-like protrusions sprout from his scapula bones that act as so. Aside from this, Shun is able to move as fast as one does when using the Raiton no Yoroi and Shunshin. While the physical transformation may seem like advantages, there is a double side to this. Shun's muscles corrode and regenerate quickly, causing intense pain while he's in this form. Also, his stamina drains slowly, causing being in this form especially dangerous for elongated periods of time.
Shun has had corrosive venom glands implanted into his salivary ducts, allowing him to produce an acid-like saliva. He, however is immune to the effects due to the glands synching with his body's own chemical levels, allowing for free usage