He could be really curious. Just like Hermione is always eager to learn new spells and knowledge, he might be constantly exploring the Hogwarts grounds, looking for hidden secrets or new magical creatures.
Well, they could be very protective of each other. Hermione, being the intelligent and strong - willed witch she is, might take it upon herself to teach her little brother all she knows about magic. And her little brother could look up to her and be her biggest supporter in Hogwarts, always cheering her on during her academic achievements and adventures.
Maybe they embark on a journey to rescue a captured wizard or witch. They use their different strengths - Hermione's strategic thinking and her brother's charm or ability to make quick friends in the wizarding world - to plan and execute the rescue mission.
In the fanfiction, they could have a very protective relationship. The brother might always be looking out for Hermione, especially in dangerous situations at Hogwarts. He could be like a secret guardian, using his own unique skills and knowledge to keep her safe.
In the fanfiction, their relationship could be one of mutual admiration. The baby brother could look up to Hermione as a role model, seeing her as a source of inspiration. And Hermione could be in awe of how quickly he picks up new things, like magic spells or concepts, and they could bond over their shared love for magic.
First, his character could start off as a bit of an enigma. Maybe he has been away from Hermione for a while, and when he returns, he realizes how much she needs protection. As the story progresses, he could show his protective side more and more. He might be a strong wizard, but also have a soft heart, especially when it comes to Hermione. He could be developed as someone who is well - respected in the wizarding community for his own achievements, and uses that status to shield Hermione. For instance, if she's wrongly accused of something, he uses his influence to clear her name. He could also have a bit of a temper when it comes to those who threaten Hermione, which adds an interesting dimension to his character.
One possible character trait is self - sacrifice. He would be willing to put himself in danger for Naruto's sake. He could also be patient. Naruto can be a bit impulsive, so an older brother would need to be patient with him. He might be a bit of an outcast too, like Naruto was in the village. But instead of being shunned for having the Nine - Tails, he could be shunned for some other reason, like having a different ideology about how the ninja world should be run. This would add depth to his character and his relationship with Naruto.
Another trait could be her sense of determination. Combining Hermione's dogged determination to right wrongs and Tom Riddle's single - minded pursuit of his goals, she could be extremely focused on achieving whatever she sets her mind to. This could range from reforming the wizarding world's political system to uncovering long - lost magical secrets. Her character would be a fascinating study in the clash and combination of her parents' very different personalities.
Her twin sister could be really outgoing. While Hermione is often seen as a bit reserved in social situations, the sister could be the life of the party. She might be more interested in Quidditch than Hermione and be a great flyer. Also, she could be more impulsive. Hermione thinks things through carefully, but the sister could be the type to jump into action without much planning.
His presence could make Hermione more responsible. She might have to take on babysitting duties, which would cut into her study time, but also teach her about time management in a new way. For example, she'd have to find time to study while also making sure her baby brother is safe and happy.
Draco's character development might involve him breaking away from the traditional Slytherin values. Being Harry's brother, he could be influenced by Harry's Gryffindor - like qualities. He might start to question the pure - blood supremacy ideas he was brought up with and become a more inclusive wizard. For example, he could start making friends with muggle - borns, which is a huge shift from his original character.