Another possible plotline is that Naruto is wrongly accused of some dark deeds. He then has to prove his innocence while also dealing with the fact that his friends and the village start to turn against him. This would create a lot of emotional turmoil for him and force him to dig deep into his own character to find a way to clear his name and bring light back to his situation.
One interesting plotline could be Naruto exploring his darker side in more depth. Maybe he discovers a hidden power within him that is related to the 'darkness' and has to learn to control it without being consumed by it.
Perhaps in this fanfiction, Naruto is lost in the darkness because of a powerful enemy's jutsu that has separated his spirit from his body. He then has to navigate a shadowy realm, meeting strange and mysterious beings that either help or hinder his journey back to the real world.
One interesting plotline could be the exploration of Naruto's new powers as the 'heir of darkness'. Maybe he has to struggle with controlling these dark powers while still maintaining his friendships in Konoha. For example, his relationships with Sasuke and Sakura might be put to the test as they are unsure how to react to his new abilities.
One possible plotline could be Naruto being betrayed by those he trusted most in the village. This could lead him to question his loyalty and values, gradually falling into darkness. For example, if the village elders secretly framed him for a crime he didn't commit, and his friends turned their backs on him without believing in his innocence.
One possible plotline could be that Naruto is constantly ostracized by the village, which slowly breaks his spirit and makes him turn to the dark side. He might start to use forbidden jutsus without any moral restraint.
A plotline could also focus on the personal growth of a particular character as they navigate through the Vale of Darkness. For instance, Ruby might struggle with her own fears and insecurities in this dark and dangerous place, but through her experiences, she emerges stronger and more confident, with a deeper understanding of her role as a Huntress.
One interesting plotline could be the protagonist's journey of self - discovery as they emerge from the darkness. They might face internal struggles like overcoming past traumas or fears that have held them back. Another could be the relationships they form along the way, perhaps with characters who help them navigate this new phase of their life.
One possible interesting plotline could be the exploration of a new power that the main character discovers, which is a result of their strong will. This power might set them on a journey to change the Naruto world in unexpected ways.
One interesting plotline could be Naruto seeing how his actions in the past have shaped the future of the Hidden Leaf. For example, if he discovers that a decision he made led to a new alliance or a new type of jutsu being developed.
A possible plotline could be the discovery of an ancient power related to darkness and flame that threatens the balance of the Naruto world. Naruto and his friends then have to find a way to either control it or destroy it.
In some 'prince of darkness harry potter fanfiction', there might be a plotline where the 'Prince of Darkness' is a misunderstood figure. He may have been misjudged by the wizarding community for centuries. And now, through his interactions with Harry Potter, his true nature and motives start to be revealed. This could lead to a situation where Harry has to decide whether to trust him or not, and it could also cause a rift between Harry and his friends who might be more suspicious of the 'Prince of Darkness'.