The first of the Sharingan's powers is being able to see the flow of chakra. The Sharingan can tell if a person is under a genjutsu because the person's chakra flow would be irregular.

The Sharingan's second-most prominent ability grants the user an incredible clarity of perception, allowing them to easily recognize genjutsu and different forms of chakra, though not to the same extent as the Byakugan. This also allows the user to pick up on subtle details, enabling them to read lip movements or mimic something like pencil movements. As the Sharingan evolves, gaining more tomoe seals, this ability extends to being able to track fast-moving objects before finally giving some amount of predictive capabilities to the user. However, even though the user may be able to see an attack or know it is coming, their body may not have time to react.

The Sharingan's third and most well-known ability is that it grants the user the ability to memorize any technique that he or she witnesses, apart from other kekkei genkai techniques. The user can memorize ninjutsu, genjutsu, and taijutsu with near perfect accuracy, allowing the user to use the techniques as their own, or even modify them to create their own new techniques. In order to reproduce a copied jutsu, however, one must have the necessary skill or ability to perform them. In addition to physical skill and kekkei genkai techniques, the Sharingan cannot reproduce jutsu dependent on other factors, such as summons that the user has not signed a contract with.

The Sharingan's final commonly-used ability is capable of inducing a unique brand of hypnosis that involves suggesting actions and thoughts to the opponent through genjutsu cast by simple eye contact. More advanced Sharingan users can take the hypnosis ability even further to the point where a powerful summons or even Bijuu’s may be controlled. When this was used against summons and the Bijuu’s their eyes took on the tomoe pattern of the users' Sharingan while under hypnotic influence.

The hypnotic ability coupled with the other aspects of the Sharingan, can make the user appear as if they can "see the future". First, the user must perfectly mimic every move their opponent makes and possibly their thoughts and words through careful observation. Then, they suggest an action to the opponent such as hand seals for a jutsu that the opponent and Sharingan user already know and copy that. With these things done, the user can complete the action even before the opponent does, possibly using the Sharingan's genjutsu to confuse or delay them. As with other genjutsu, genjutsu cast by the Sharingan are capable of putting an opponent to sleep, inducing paralysis, replaying memories to someone else, or creating various illusions to deceive someone. The potency of the Sharingan's illusion is dependent on the user's knowledge and skill with implementing genjutsu.
Although the Sharingan consumes the user's chakra while active, the chakra levels that the user must exert is so insignificant that they can keep it active constantly. However, when a Sharingan is transplanted to a non-Uchiha, the chakra drain is significant, leading them to cover it up when not in use, to stop the drain.

The Mangekyō Sharingan gives the user access to several powerful techniques, including the powerful fire jutsu Amaterasu and the almost unbreakable genjutsu Tsukuyomi. The Mangekyō Sharingan erodes the eyesight of its users, eventually causing blindness, which can be prevented by obtaining another pair of Mangekyō Sharingan from a sibling. The new Sharingan is dubbed the Eternal Mangekyō Sharingan.

The Uchiha clan descended from the elder of the two sons of the Sage of the Six Paths. The elder brother inherited the Sage's "eyes", powerful chakra and spiritual abilities. When it came time for the Sage to choose a successor, he questioned the two on what course of action they would follow to bring order to the world. The elder believed that might was the way to bring peace, while the younger believed love was the way. The Sage favored the ideal of the younger brother, and therefore designated the younger as his successor, causing the elder to be filled with jealousy and hatefulness. From the younger son descended the Senju clan who would be the eternal rivals of the Uchiha.

Before the founding of the ninja villages, the Uchiha were one of the many mercenary clans for hire. Because of their Sharingan, the Uchiha clan came to be known as one of the two strongest clans, the other being the Senju clan. As time passed the Uchiha grew stronger, conquering whatever clans they came upon, such that, whenever the Uchiha clan was hired for a job, the opposing side would hire the Senju, and vice versa.

The Senju clan, grew tired of the endless fighting, and approached the Uchiha clan with a peace treaty. The leader at that time feared that an alliance would lead the Uchiha to ruin, but his clan disagreed, and he was forced to accept. The two clans came together to stop fighting. The Senju settled in the Cherry Blossom Country, and the Uchiha moved to the Ocean Country to reside on its various islands. What happens next will depend on the generations to come.

Ren'ai's parents were considered "noble" Uchihas with much influence in their own clan and in Shippuugakure itself. At one point, her own father had been considered as an Umikage, but more notable shinobi had found the position over her father. Her mother was a skilled assassin and continued to do assassinations while pregnant with Ren'ai; she kept up the assassinations until the day before birth. Ren'ai was birthed on the first day in years that her mother had not taken a life- as such, her father named the girl Ren'ai- which translates as love/passion.

Ren's birth brought a change in her mother and began a new lifestyle of passion for her clan rather than just for the killing. Their family quickly became respectable and honored, no longer feared and envied. Ren was raised in a loving environment with a very caring mother and a prominent father who always required her to be the very best she could be. Even to this day, her mother fills her with unfathomed love and her father expects her to be the best she can be for her clan; he is a kind man himself but seems cold sometimes to bring about an intended goal or change in her.

Her family and lifestyle are quite the opposite of the normal uchiha family, their passion is for the love of their clan and village, not revenge and hate. Ren was raised as a very young child to enjoy her clan and learned to love them; the good and the bad alike. Much is expected from Ren'ai and a lot of pressure is put on her shoulders to make sure she surpasses the legends of both her father and mother- even they want her to shine brighter.

Ren's lifestyle led her to be mischievous even if only on a small scale, always being the "model daughter" taught her many things of how to get away with stuff without getting caught. From an early age, she was aware that her body had developed much more than some women and she was often treated with jealousy because of this. She found herself the target of hate from older women who she looked up to because her body made them feel inferior as a woman and a woman's charm. She came to understand the woman's charm from an early age and even how to use it properly to often get what she wanted. Even now, she often teases those close to her just because she grew up that way.