There is a possibility that it was an ex - shinobi who had retired from active duty. This person had amassed a collection of seals during their career and now made a living by selling them to other ninjas like Naruto.
Well, considering Naruto's own experiences and the variety of seals in the Naruto universe, he could sell communication seals. These would allow ninjas to send messages over long distances. He might also sell seals that are related to elemental jutsu, perhaps ones that enhance or modify fire, water, wind, earth or lightning techniques.
Perhaps Naruto was in a situation where he had made a deal. For example, he promised to pay for the seals in exchange for some information about a missing nin or a secret technique. He values knowledge and power, and if paying for the seals was part of getting closer to achieving his goals, he would do it.
The seals could also be a plot device for a darker storyline. Maybe they were placed by an unknown enemy to control Naruto or use him as a weapon. In some fanfictions, the seals start to affect Naruto's mental state, causing him to have inner struggles between his normal self and the influence of the seals.
In some fanfics, Naruto might use his new and powerful jutsu that he has mastered over time. Maybe he combines his Sage Mode with the power of the Nine - Tails in a unique way that Orochimaru can't counter. For example, he could use the Nine - Tails' chakra to enhance the range and power of his Sage Mode attacks, and then catch Orochimaru off - guard.
Well, in some versions, Naruto might use his new and improved Rasengan techniques. He could have combined it with his Sage Mode powers to overpower Orochimaru. Maybe he also uses his quick thinking and the element of surprise, since Orochimaru is always so full of his own schemes.
Kabuto is also common. He was Orochimaru's right - hand man. In fanfiction, he could be used to either further Orochimaru's plans against Naruto or he could have a change of heart and help Naruto against Orochimaru. His medical skills and knowledge of Orochimaru's secrets make him an interesting addition to the story.
Yes, there might be some fanfictions with such a plot. In the Naruto universe, it's a very wild and out - of - the - box concept. Some fanfiction writers like to explore such non - canon relationships to create unique storylines. However, it's not part of the original Naruto story.
One consequence could be a shift in the power balance among the ninja villages. Since Orochimaru was a powerful and feared figure, his death might cause some chaos as his former allies or subordinates try to either avenge him or claim his resources. For example, some of his secret labs and experiments might be up for grabs, leading to potential conflicts.
I'm not sure exactly as there could be many different interpretations. It might be about new types of seals in the Naruto universe and how they affect the fate of the characters. Maybe it focuses on a character who discovers a powerful seal that changes the course of their life or the entire ninja world.