Debuting in manga volume 49 and anime episode 201 of Naruto Shippuden. Shisui Uchiha resembled his ancestor Kagami Uchiha in appearance, with short, untidy, dark-colored hair, black eyes, a moderately large nose, and well-defined eyelashes that turned upwards at either end. Shisui was a very modest and down-to-earth person. He was never overweening about his own talent or accomplishments, but he was not afraid to tell others when they were wrong.
At the same time, he was open-minded, never clinging to a single ideal, and strived to recognize the unique character of the current scenario before him. Shisui was also a genuinely sympathetic guy, especially toward his adversaries, expressing pity and tenderness to a dying Mukai Kohinata while being commanded to murder him as a traitor. He was also demonstrated to be incredibly insightful and intuitive from an early age, able to see through the emotional character of others and to notice even the slightest facts around him. Shisui grew to love Itachi and treated him as though he were a big brother.
Shisui was committed to his clan, but he was also devoted to the well-being of his village, which his own clan seemed to be unaware of. His love for his town was so deep that he never succumbed to the Curse of Hatred. Shisui, on the other hand, had a darker side that he was profoundly ashamed of; out of jealously for a buddy who he felt had exceeded him in talent, Shisui delayed help at a vital moment, resulting in the death of the other shinobi. Shisui became convinced that he was a murderer as a result of his actions, prompting him to awaken his Mangeky Sharingan, which he utilized as a continuous reminder of his sorrow and pledge to never succumb to such sentiments again.
Shisui graduated from the Academy during the Third Shinobi World War and was assigned to a genin squad with his best buddy. Shisui observed his companion die on a mission shortly after the war ended a year later, which triggered the Mangeky Sharingan since he felt guilty. A year later, he met Itachi Uchiha, a 5-year-old boy with whom he became best friends and built a brother-like attachment. Shisui began attracting notice as a genin a year later, earning the moniker “Shisui of the Body Flicker” for his use of the Body Flicker Technique.
Shisui’s bedridden father ceased to recognize him two years later due to his declining health after getting ill as a result of his losing his leg in the previous world war. Shisui was prepared for his death, knowing that everyone dies at some point. Shisui handed his left eye to Itachi, instructing him to preserve both the village and the Uchiha name, fearing that Danzo was correct in his assessment of Shisui’s incapacity to put down the Uchiha insurrection.
Shisui prepared a suicide letter in which he stated that he could not carry out the coup d’etat, but his clan’s narrow-mindedness prevented them from comprehending his wish for peace and reconciliation. The suicide notes had necessary information about his thoughts about how it appears that he had crushed his eyes when jumping off a cliff into the water body known as the Naka River to escape the clan feud leaving no trace of himself. Shisui also wanted to exploit his death in the anime to awaken Itachi’s Mangekyo Sharingan, and he was successful.
Will Shisui return?
Shisui’s comeback is unlikely, but given the series’ track record, it’s feasible he might have a lasting impact on the plot that stretches even beyond Boruto. While his body was never discovered, it’s theoretically likely that Kara, in their efforts to experiment with ninja technology, discovered and used some vestige of his body. It just so happens that the remnant is from Shisui, resulting in an embarrassing entrée into the plot.
It’s quite improbable, considering we’ve previously proven that Shisui died and properly disposed of his body. It’s difficult to imagine how you’d discover him if even Konoha’s greatest looked and found nothing. And even if he could return, what function would he serve in the story? Nobody knows who he is, and he is a relic from a bygone period.
Do you use Kotoamatsukami? All of his eyes have vanished. You’d have to use ninja tech to get a comparable result. Shisui can be an inspiration, but he can’t be a part of it. He’s already gone. From a writing standpoint bringing him back would only cheapen the impact and legacy of his death, his eyes are gone and we know how important of a factor that is already, Sasuke isn’t likely to resurrect him and the fall from which he committed suicide was so big that surviving from it seem s very unlikely and unrealistic.
Kabuto was unable to find the body of Shisui during the 4th Great Ninja War. His reappearance is possible via flashbacks, although it is unlikely. If he does appear in flashbacks, it will be Sasuke informing Boruto or Sarada about the Uchiha family’s history and his own. But everything essential about Shisui comes from Itachi’s past, not Sasuke’s. Flashbacks from Sasuke’s youth would most likely focus exclusively on Itachi and his family, rather than the three tiny interactions Sasuke and Shisui experienced.