In the fanfiction, once Naruto finds the secret lab, he could come across a device that can enhance a ninja's chakra control exponentially. However, this device might have some negative side effects. He may also find some records in the lab about the true origin of the ninja world or some long - forgotten prophecies. This discovery would set him on a new journey to uncover more about the ninja world's past and how it might impact the present and future.
He might discover some new and powerful jutsu hidden there. Maybe it's a lab created by an ancient ninja clan that was lost to history.
He might discover some long - lost jutsu. Ancient labs could hold secrets to powerful ninja techniques that have been forgotten over time. Maybe he'll find scrolls with unique chakra - based abilities or old - fashioned weapons with special powers.
Perhaps Percy was lured to the research lab by some unknown force. When Artemis finds him, she realizes that there is a greater danger at play. They could team up to figure out what's really going on. Percy might use his unique skills and knowledge, while Artemis uses her divine powers. Together, they could uncover a conspiracy or a hidden secret in the research lab that no one else knew about.
Well, Naruto might first try to free Kaguya. He is a hero after all and doesn't like to see anyone chained unjustly. But he would also be very cautious because Kaguya is extremely powerful and was once a great threat. He could try to communicate with her to understand why she is chained there in the first place.
Another scenario could be that Naruto discovers a hidden chamber in the lab. Inside, there are test subjects that Orochimaru was using for his immortality experiments. Naruto feels sympathy for them and tries to rescue them. However, he has to figure out how to deal with the various traps and security measures in the lab first. He might call for help from his friends like Sakura or Kakashi to assist him in this difficult task.
Perhaps in this fanfiction, the secret library is guarded by some sort of magical or powerful entity. Naruto, being Naruto, would try to befriend it first. Once inside, he could find prophecies about the future of the ninja world written in the books. This knowledge might put him on a new path of preventing future disasters and bringing about a new era of peace in the ninja world.
The lab could hold secrets about Orochimaru's past. Maybe there are records of his early days as a ninja, his training, and what led him to become so obsessed with immortality. Naruto might stumble upon these records and gain a better understanding of his enemy.
In the fanfiction, Naruto could meet someone who knows a lot about the Kusanagi. This person could be an old sage or a mysterious traveler. They could teach Naruto how to use the sword properly and unlock its true potential. It could also lead to Naruto getting into some battles where the Kusanagi gives him an edge, and he has to learn to adapt his fighting style to include swordplay.
Maybe Naruto discovers the violin and is instantly intrigued by its sound. He might try to learn how to play it, seeing it as a new form of self - expression. Since Naruto is known for his determination, he could struggle at first but then gradually master the instrument.
In the fanfiction, Naruto might take the puppy back to the village. He could name it something cute like 'Kiba Jr.' and train it to be a helpful ninja dog.
Well, Naruto might take the egg to his home and try to figure out what kind of creature is inside. Maybe he'd ask Kakashi for advice on how to take care of it.