Perhaps Naruto's death on the mission could be due to a powerful new enemy that the village was unaware of. This could lead to a period of chaos as the village scrambles to figure out who this enemy is and how to combat them. His death might also cause a rift between different factions in the village, some blaming the Hokage for sending Naruto on such a dangerous mission, while others understand it was necessary for the greater good.
In the fanfiction, Naruto's death on the mission could result in Hinata going into a deep depression. She might struggle to raise their child (if they have one in the fanfic) alone. The child, growing up without Naruto, could be determined to learn about his father and become a great ninja like him. This could drive the plot forward as the child discovers secrets about Naruto's mission and the real reason behind his death.
One way the story could be developed is that Naruto's death could trigger a chain of events within the Hidden Leaf Village. His friends, like Sasuke, might be filled with guilt and anger. Sasuke could vow to avenge Naruto and start a dark path of seeking extreme power. Meanwhile, the village would be in mourning, and the younger generation would see Naruto as a martyr, inspiring them to train harder to protect the village in his memory.
One way could be that Naruto jumps in front of a powerful attack meant for Haku. Maybe in a battle where Haku is protecting someone Naruto cares about, and Naruto's selfless nature makes him sacrifice himself. Then the story could focus on how the other characters react to Naruto's death, like Sasuke feeling guilty for not being there or Sakura being heartbroken.
It could be a rogue ninja from a neighboring village. Maybe they were hired by a shadowy organization that wanted to disrupt the balance of power. This ninja might have been specifically targeting Naruto because of his status as a hero and a symbol of hope for the Hidden Leaf Village.
A new organization that is bent on world domination could be the main antagonist. They set a trap during Naruto's mission. This organization might have access to some ancient and forbidden jutsu that they use against Naruto. They see Naruto as a major threat to their plans, so they target him specifically.
One possible plotline could be that Naruto is on a highly dangerous mission alone, perhaps against an extremely powerful and unexpected enemy. He might sacrifice himself to protect his village or his comrades. For example, he could be facing a new type of jinchuriki whose power he underestimated, and in the end, he uses all his strength to seal the enemy away, but at the cost of his own life.
One way the story could be developed is by showing Naruto's reasons for becoming a pickpocketer. Maybe he's desperate to help his village in some way and sees pickpocketing as a quick solution. For example, he could be stealing from the rich to give to the poor in Konoha. This would add a Robin - Hood - like aspect to the story.
In the fanfiction, their love story could be set in a new world where both Naruto's and Rias' universes collide. Maybe Naruto is on a mission in Rias' world and they meet by chance. Naruto's unique powers like the Rasengan would be a novelty in Rias' world, and she would be intrigued. As they get to know each other, they start to care for one another, and love blossoms. It could also involve some cultural exchanges between the two different settings.
One way could be through some sort of magical or cross - dimensional event. Maybe a powerful magic user or a godly artifact messes up the fabric of different mythologies and universes, bringing Naruto and Aphrodite together. Naruto, with his strong sense of loyalty and justice, might initially be very confused by Aphrodite's beauty and the concept of Greek gods.
In a fanfiction where Naruto is the villain, perhaps he becomes corrupted by the Nine - Tails' power. The constant struggle to control the fox within him finally takes a toll, and instead of fighting it, he gives in. He then uses the Nine - Tails' brute strength to wreak havoc. He might see the shinobi world as a place full of hypocrisy and decides to 'cleanse' it by force, attacking villages one by one, starting with Konoha, which he now views as a place of false promises.
Well, in this fanfiction, it could start with Naruto realizing his deep feelings for both Ino and Sakura over time. For the plot development, perhaps they go on a mission together where they have to rely on each other in a new way. Naruto might have to balance his time and affection between the two. Ino could help with strategic planning in their family life, and Sakura would take care of their health. Eventually, they form a unique family unit that is accepted in the village because of their combined contributions.
One way could be that Naruto has been in a time - loop for a thousand years. He keeps reliving certain events, trying to change the outcome each time. For example, he might be trying to prevent a great war that keeps happening no matter what he does in each loop.