He might become more guarded and secretive. Naruto is usually very open, but leading the League of Shadows would require him to keep some things under wraps. However, his core of kindness would still remain, and he'd try to use it to influence the members in a positive way.
Naruto's personality would experience a significant transformation. He is used to the bright and open - minded world of Konoha. In the League of Shadows, he'd be surrounded by secrecy and a different set of values. His loyalty would be tested, and he might become more cynical. He'd have to question his own beliefs and values more often. His exuberant and friendly nature could be replaced with a more guarded and reserved one. He might start to see the world in a more complex and less black - and - white way, which would be a huge change from his original self.
One idea could be Naruto using his unique skills and values to reform the League of Shadows. He might introduce a new code of honor that focuses on protecting the weak rather than just causing chaos. His Rasengan could be modified into a more stealthy and strategic attack for the League's operations.
Naruto's character would become more self - reliant and less likely to trust others easily. The League of Shadows' training would instill in him a sense of survival at all costs. He may develop a cold exterior to hide his true feelings. For instance, instead of being the loud and enthusiastic Naruto we know, he could be a quiet and calculating ninja. His values would be shaped by the League's ideology, which could lead to him having a different view on things like loyalty and sacrifice.
He becomes more decisive. As a leader, Naruto can't afford to be indecisive like he sometimes was in his youth. He has to quickly make choices that affect the whole village or group he's leading.
If Batman joined the League of Assassins in fanfiction, his personality would likely change quite a bit. He'd probably become more cynical. The League's cut - throat environment and their disregard for human life (to an extent) would make him question his own methods of protecting Gotham. He might also become more secretive from his usual allies, as he'd be involved with a very dangerous and secretive organization. He could develop a more ruthless streak, but still hold onto some of his core values deep down, which would cause internal turmoil.
He might become more assertive and decisive. Normally, Percy is a bit of a reluctant hero, but as a gang leader, he'd have to make quick decisions to protect his gang. He could also become more secretive, as gang activities often need to be kept under wraps.
He might become more assertive. Normally, Harry is somewhat hesitant at times, but as a gang leader, he'd have to be quick in making decisions. For example, when facing an enemy attack, he can't afford to be indecisive.
Well, in such a fanfiction scenario where Naruto joins the League of Shadows, he could introduce new training methods. His Uzumaki chakra and unique jutsu might change the power dynamics within the League. Also, his relationship with the existing members would be complex. Some might see him as an asset, while others could be suspicious of his motives.
The 'Naruto Raised by the League of Shadows' fanfiction would open up a whole new world of possibilities. Naruto would grow up in an environment full of secrecy and danger. He could be trained in unique jutsu that are exclusive to the League. His relationships would be completely different. For example, he might not have the same bond with Sasuke or Sakura. Instead, he would form alliances with the members of the League. His moral compass would be constantly tested as he is exposed to the League's often amoral actions.
If Naruto becomes involved with Slenderman in a fanfiction, his usually cheerful and determined personality might become darker. He could be more withdrawn as he grapples with the strange and often terrifying aspects of Slenderman's world.