You could also introduce the new character through a crisis situation. Say there's an unexpected attack during the Chunin Exams and this new character steps in to help. This shows their skills, courage, and also gives an opportunity to start building relationships with the other characters right away. They can then become an important part of the story as it progresses.
A new character can be introduced by making them a mystery at first. For instance, they could be seen observing the exams from the shadows. Then, gradually reveal their abilities and motives. Maybe they have a special connection to one of the existing characters, like being an old acquaintance of Kakashi's from his travels.
Another way is to introduce them as a competitor. Give them a unique fighting style or power. For example, they could have a power related to nature manipulation in a very different way than we've seen before in the Naruto world. They can start by impressing the crowd with their skills during the early rounds of the Chunin Exams.
There could be a new character who is a descendant of an ancient clan that once had the Rinnegan. This character might show up during the Chunin Exams to either help or hinder the current Rinnegan user. They might have some knowledge about the Rinnegan that others don't. Also, an anti - Rinnegan organization's agent could be introduced. They would be there to try and eliminate the Rinnegan user during the exams, thinking they are a threat to the balance of power.
Well, in certain fanfiction about the Chunin Exams, Naruto could be seen as brutal because he might take advantage of his opponents' weaknesses in a rather ruthless way. He may not give them a chance to recover or adjust their strategies. Say, if an opponent is vulnerable after using a big move, Naruto might immediately strike with a powerful counter - attack instead of waiting for a fair rematch. This makes him seem brutal as it goes against the more sportsman - like nature of the regular Chunin Exams.
A new character could be a young Uchiha who has just awakened their Sharingan but is very shy and inexperienced. They enter the Chunin Exams and are constantly underestimated because of their quiet nature. But as the exams progress, they start to show amazing potential with their Sharingan, for example, being able to quickly analyze and copy complex jutsu. Another interesting character could be a non - Uchiha who has studied the Sharingan extensively and has developed techniques to counter it. This character would add an interesting dynamic to the Chunin Exams as they would be a threat to the Uchiha participants.
A blind kenjutsu master in training. He has developed a unique way of sensing his opponents' movements through chakra flow. In the Chunin Exams, he would be a real wildcard as other characters wouldn't be used to fighting someone with his abilities.
Well, in a Chunin Exams fanfiction, Dark Naruto's character development could be very different from the original Naruto. At first, he might be all about causing destruction and chaos. But as the story unfolds, he could be forced to confront his inner demons. Maybe he has a moment of self - realization when he sees the consequences of his actions on the other participants of the Chunin Exams. This could lead to a slow transformation, where he starts to understand the value of friendship and the ninja way, but in a more tortured and complex way compared to the regular Naruto.
One idea could be focusing on a character other than the main ones during the Chunin Exams. For example, showing how a minor character from another village is dealing with the pressure and the politics behind the exams. Maybe they suspect some cheating going on among the big villages and are trying to expose it while also competing.
One unique character could be a young prodigy from a small, secluded village that has been in isolation for a long time. This character might have developed a strange and powerful kekkei genkai that no one else has ever heard of. They could be shy and reserved at first but show their true strength during the Chunin Exams. Also, a character who was once a criminal but has reformed and is now trying to prove themselves in the exams. Their past experiences as a criminal would give them a different perspective and set of skills compared to the other genin.
In this fanfiction scenario, Naruto and Yugito could have some really interesting interactions during the Chunin Exams. Maybe they start off as rivals, each determined to prove themselves in the exams. Naruto with his unwavering determination and Yugito with her unique skills. They might end up in a match against each other, and through the battle, they gain a newfound respect for one another's abilities.
One idea could be that Naruto forms an unexpected alliance with Anko during the Chunin Exams. Maybe they team up to uncover a hidden plot within the exams that threatens the safety of all the genin. Anko, with her experience, could help Naruto see things from a different perspective and he, in turn, could inspire her with his determination.
One idea could be that female Naruto has unique jutsu in the Chunin Exams. For example, she might have a more refined version of the Shadow Clone Jutsu, which surprises the opponents and judges. Her character could also show more emotional intelligence during the exams, like using her understanding of others' feelings to her advantage in battle, perhaps by predicting their moves based on their emotions.