Yeah, no we shouldn't allow this to go any further.
We definitely shouldn't play along. That might just encourage him to try again. The fan was given to us by our mom on our first day of school. Turning it into some weird game with Naruto is stupid. If this was Mariko or some other random bully we wouldn't just laugh it off and make a game of playing keep away with a prized possession. We would make it clear that there are lines that shoudn't be crossed. Naruto wants to be treated like a normal person, fine we can treat him like a normal person.
[X] Explain to Naruto that he stole a prized possession given to you by your mom and you would appreciate having it back. If he doesn't give it back, then you can go ahead and beat him until he gives you your fan back. Diplomacy should be attempted first before moving on to other forms of aggressive negotiations.
@Vesvius how's this for a write in?
How do you know he won't harm the fan. If we encourage this behavior of keep away it will likely be damaged in the future.