In Naruto fanfiction, the combination of Fuinjutsu and blacksmithing can be really interesting. Fuinjutsu is all about sealing techniques, and when combined with blacksmithing, one can imagine creating weapons with sealed powers. For example, a sword that has a sealing jutsu inscribed on it to trap the opponent's chakra when it strikes. It adds a whole new layer of creativity to the Naruto universe.
In such fanfiction, the blacksmith could be a master of both metal and seals. They might create a chain with Fuinjutsu that can bind an opponent's chakra. This would be a great addition to a ninja's arsenal. They could also work on larger items like gates with Fuinjutsu seals to protect a village or a secret location.
It could also be a new character created specifically for the fanfiction. This character might be an old hermit who has been living in Konoha in secret and is now passing on his knowledge of Fuinjutsu to Naruto or other characters. Maybe he has a special connection to the founding of Konoha and the original development of Fuinjutsu.
One interesting aspect in Naruto fanfiction about Fuinjutsu in the Chunin Exams could be a character using unique Fuinjutsu techniques that were not shown in the original series during the exams. For example, a genin might create a sealing jutsu to temporarily disable an opponent's chakra flow in a creative way that surprises everyone.
Well, Naruto is an obvious choice. His connection to the Nine - Tails and his determination to master different techniques make him a central figure in many 'naruto fuinjutsu bloodline fanfiction'. Sakura might also be popular as she evolves in her skills and could be part of a story where she discovers a bloodline - related to fuinjutsu. Then there's Gaara. His unique sand abilities which could be related to a hidden bloodline in fanfiction and his connection to sealing jutsu in some storylines make him a popular character as well. There are also original characters created by fanfiction authors that can gain popularity within the specific context of this type of fanfiction.
Perhaps in a fanfic, there could be a group of rogue ninjas who use Fuinjutsu to steal the secrets of the Chunin Exams. The main characters would then have to use their own knowledge of Fuinjutsu to stop them. They might combine different sealing techniques to counter the rogues' attacks.
I'm not entirely sure if there is a specific one with that exact premise. However, fanfiction authors are constantly coming up with new and unique concepts. Given the popularity of both Harry Potter and Naruto, it's possible that someone has written a story where Harry Potter is a blacksmith within the context of a Naruto fanfiction. It could be an interesting take on the characters and their worlds, perhaps exploring how Harry's skills as a blacksmith could interact with the ninja world of Naruto.
Well, in 'naruto fuinjutsu bloodline fanfiction', a cool concept is the idea of a hidden bloodline that has been lost for centuries but holds the key to the most powerful fuinjutsu. This bloodline might give the user the ability to not only break any seal but also to rewrite the rules of existing fuinjutsu. Also, the concept of a bloodline that can transfer fuinjutsu knowledge through genetic memory can be really fascinating. It means that the user doesn't have to study as hard to master complex fuinjutsu as they inherit the knowledge.
One popular fanfiction where Naruto learns Fuinjutsu is 'The Seal Master Naruto'. In this story, Naruto discovers an ancient scroll that teaches him advanced Fuinjutsu techniques. It's a great read as it shows his journey from being a novice to a master in the art of seals.
Well, they might have the ability to create extremely powerful sealing jutsus. For instance, they could seal away powerful demons or enemies with ease. Just like how the Fourth Hokage sealed the Nine - Tails in Naruto, the Fuinjutsu master could do similar things but perhaps on an even grander scale.