Dear Ninja,
We have received feedback concerning Sakura [Great Ninja War]'s issue, the feedback received was that the game would freeze when she used her Mystery Skill. We would like to inform you all that this bug has been fixed. Please, clear your cache and log in to the game again to correct this bug. We are truly sorry for any inconvenience this issue might have caused. Thank you for your understanding.
Best regards,
Naruto Online Support Team