Villains in stories often and should be challenges to hero beyond the physical whether that be emotional, psychological, or ideological. This is often done by the villain being a dark reflection of the hero; often of a certain trait to both challenge and warn the hero.
In the latest chapter of the Mirai manga it made pretty clear the Ryuki is a dark reflection of Mirai's dissatisfaction of the current era. That they, by living in an era of peace are unable to match the generation that came before them.
In Kotor II: The Sith Lords. The Titular Villains, the Sith Lords, are a dark reflection of the heroine the Jedi Exile. The Jedi Exile was a general in the Mandalorian War with an innate talent to create force bonds to strengthen her, during the final battle of the war she was betrayed by her leader, Darth Revan, by being order to activate a doomsday weapon the Mass Shadow Generator, the backlash of the mass death happening all at once made her cut herself off from the Force, but she in the game comes back defeats the Sith and her students go on to restore the Jedi Order that lasted for nearly 4000 years after her death. Darth Nihilus, Lord of Hunger, was an extreme of her relying on her force bond power to feed off others for strength; he became so consumed by his own power, he consumed his own body, and had to bind himself to his armor to survive. Darth Sion, Lord of Pain, is a dark reflection of her relying on the force to sustain herself; he became a walking corpse that could only survive by the Force. Darth Traya, Lord of Betrayal, both were betrayed by the Sith and exiled by the Jedi; Traya all the Jedi she trained followed Revan and fell to the darkside, she trained the other two lords in how to use their power which led to being consumed by their power, then betraying her, and she trained the Exile for revenge. Beyond the Exile, no other student survive to pass on her teaching leading them to mostly die with her beyond what the Exile taught to the Jedi. As Traya is the final boss she therefor is the greatest of the dark reflections of the Exile. IE Darth Revan's betrayal or in the game desire for revenge against the Jedi Council for exiling her was the greatest danger that could have led to her falling to the darkside.
Back to Naruto. As Obito is Naruto's greatest dark reflection he represents what is the greatest danger of what could make Naruto fall. Sakura's death at the hands of Sasuke. Why is that? Because, until the last moment of the manga, he was in love with her! That's why Naruto understood and forgave him. Without Naruto's love of Sakura, the story doesn't work.
Edited by Bail o' Lies, 26 June 2023 - 01:12 AM.