Many times, she has a kind heart. Harry has been through a lot of hardships, and a kind - hearted girl would be able to comfort him. She could be the one who volunteers at the Hogwarts hospital wing, taking care of the injured students, and her kindness towards everyone, especially Harry, makes her a likely candidate for his secret girlfriend in the fanfiction.
Often, she is intelligent. In the world of magic, intelligence can be shown in various ways like being good at spells or understanding complex magical theories. This would attract Harry as he himself is quite smart. For example, she might be able to solve a difficult magical riddle that has stumped others, including Harry.
She is usually brave. Given Harry's constant battles against the dark side, his secret girlfriend in fanfiction would need to be brave enough to stand by his side. Maybe she's not afraid to face a dark wizard when protecting Harry or his friends, showing her courage in the face of danger.
Often, she is depicted as strong - willed. Since Naruto is a very determined character himself, having a girlfriend with a similar trait can create interesting story arcs where they support and challenge each other.
Another scenario could be that they start off as friends or classmates and gradually develop feelings for each other without realizing it at first. Then they keep it a secret because they are not sure how the other person really feels or they are afraid of ruining their friendship. In this case, there could be a lot of internal monologues and awkward moments between them in the fanfiction.
It could be a Muggle - born witch who he meets outside of Hogwarts during the summer holidays. She's not part of the typical wizarding society he's used to, so they keep it a secret as it's an unusual situation for a wizard like Harry to be involved with a Muggle - born in such a way.
Some common original character traits in Harry Potter fanfiction could be having a unique magical ability. For example, an oc might have the power to control the weather within the Hogwarts grounds. This can add an interesting dynamic to the story as it interacts with the existing magical elements in the Potterverse.
There could be an original character created just for the fanfiction to be Harry's secret girlfriend. Writers often introduce new characters to add new plotlines and romantic interests for the main characters.
Well, in a lot of Harry Potter fanfiction, Flint is often depicted as a proud character. He takes pride in his Slytherin heritage and his position as Quidditch captain. Also, he can be seen as a bit of a traditionalist, adhering to the old - fashioned Slytherin ways. For instance, he might look down on newfangled ideas or those who don't conform to the strict Slytherin hierarchy as it has been for generations. He is also sometimes shown as having a bit of a temper when things don't go his way, especially in matters related to Quidditch or the reputation of Slytherin house.
In many Animagus fanfics with fem Harry Potter, she uses her Animagus form to break gender norms in the wizarding world. Her form may give her more freedom to move around and be more assertive than a typical female witch in that setting.
A Gary Stu in Harry Potter fanfiction often has overly perfect qualities. For example, he might be extremely powerful magically from the start without much effort. He could also be adored by all the main characters immediately. They are usually the center of every important event and seem to solve every problem with ease, which can sometimes make the story less interesting as it lacks the real struggle and development that the original Harry Potter series had.
One common trait is a strong connection to Hogwarts. Since the founders built the school, the heir often has an almost instinctive knowledge of its layout, secrets, and magic. Another trait could be a particular moral or ethical code that aligns with the values of the founders, like fairness for Hufflepuff's heir or wisdom for Ravenclaw's.
A common trait is their intelligence. They are often much smarter than ordinary snakes. Another trait is loyalty to their owners. They will usually stay by their side through thick and thin.