Fatigue could be a reason. All those battles and saving the day can be physically and mentally exhausting. He might reach a point where he just can't take it anymore. For instance, if he has to fight back - to - back villains without much rest in between.
One reason could be that he gets tired of the constant danger and the toll it takes on his personal life. He might have lost too many loved ones due to his superhero identity, and he just can't bear the pain anymore.
One possible reason for Adrien to quit being a hero in fanfiction could be the toll it takes on his personal life. Constantly having to balance his superhero duties with his normal life, like school and relationships, might become overwhelming. For example, he might miss out on important events with his friends or family due to his hero responsibilities. Another reason could be a moral conflict. Maybe he discovers some dark secrets within the hero community that make him question whether he wants to be part of it anymore. Also, he could be forced to quit if his identity is exposed and it puts his loved ones in danger, so he decides to step away to protect them.
One reason could be the excessive toll on his personal life. He might have realized that being a shinobi means constantly sacrificing his time with family and friends. For example, he missed out on important moments in his son's life. Another reason could be disillusionment with the shinobi system. He may have seen the corruption or the never - ending cycle of violence within it and decided he no longer wanted to be part of it.
One possible reason could be that he gets tired of the constant fighting and bloodshed. He might have seen too many friends get hurt or die, and it just becomes too much for him to bear. Another reason could be that he discovers a new purpose in life outside of being a ninja, like focusing on family or helping the village in a non - combat way.
One possible reason could be the overwhelming stress. Being Hokage means handling a lot of political, social and security issues in the village. Naruto might just feel that he can't take it anymore and decides to quit in the fanfiction. For example, dealing with the constant threats from other villages and internal disputes within Konoha can be mentally and physically exhausting.
Maybe he realizes that the shinobi world is too corrupt. There could be political intrigue and power struggles that go against his ideals. He has always fought for peace and unity, but if he sees that the system is beyond repair, he might choose to quit. Also, he could have a family situation that requires him to step away from the shinobi life. For instance, if he has a child with special needs that demands his full attention.
One reason could be that the writer wants to create a new plot twist. Maybe Snape's character has fulfilled its purpose in the fanfiction's storyline and his quitting can lead to new developments for other characters.
If Adrien becomes Hawkmoth in fanfiction, Paris would be in for a major shock. His friends, like Nino and Alya, would never suspect him at first. And Marinette, who is Ladybug, would be facing a completely different kind of enemy. She's used to fighting Hawkmoth as this unknown figure, but now it's someone she knows so well. It would change the dynamic of their battles entirely.
One reason could be that he's in a state of shock. Maybe he witnessed something really traumatic that made him unresponsive. For example, if he saw Ladybug in a life - threatening situation and couldn't do anything to help immediately, it might have sent him into a state of mental paralysis.
Maybe he was framed for a crime he didn't commit. Some jealous rival could have set him up to get him out of the way.