In a fanfic, the lightning scar could be a portal. Harry discovers that when he concentrates hard enough and uses a special incantation, he can use the scar to travel to different times in the wizarding history related to Voldemort. He uses this ability to learn more about his enemy, but also risks changing the past and the future of the wizarding world.
Another plotline might be that the lightning scar becomes a target for a powerful dark wizard who wants to steal its power. This wizard believes that the scar holds the essence of Voldemort's power and if he can extract it, he can become the most powerful wizard. Harry has to protect his scar while also trying to find a way to permanently remove the threat of this power - hungry wizard. He might seek the help of old and new allies, and along the way, discover new things about his own connection to the scar and the magic within it.
Well, he might become more cunning and calculating. Maybe he starts to use more devious means to achieve his goals, like Scar from 'The Lion King' who was always plotting. He could also become more self - centered and less concerned about the well - being of others around him.
In some fanfictions, Harry's scar might hurt because of dark magic remnants. Maybe there are leftover spells from Voldemort that still linger and cause pain. It could also be a sign of a new threat emerging, like a hidden follower of Voldemort trying to use dark magic in a new way that affects Harry through his scar.
In Harry Potter fanfic, 'lightning on the waves' could potentially refer to a magical phenomenon. It might be a spell that creates lightning - like effects over water bodies. For example, a powerful wizard could use it during a battle near a lake or the sea to create a distraction or attack their enemies. It could also be a metaphorical description of a situation, like a character's sudden realization or a dangerous event that occurs on water and is as sudden and striking as lightning.
Well, in Naruto fanfiction, if there's a lightning wave, it could be related to the Uchiha clan's Sharingan abilities combined with lightning release. For example, a Uchiha character might be able to manipulate lightning into a wave - like form to attack multiple enemies at once. In Harry Potter fanfiction, the lightning wave could be a spell that was long forgotten but rediscovered by a young and adventurous wizard. It could be a spell that is difficult to control and has both positive and negative consequences, depending on how it's used in the story.
Well, it might lead to Harry having to isolate himself. If the pain is severe and constant, he may not be able to function normally in his daily life at Hogwarts or in the wizarding world. He could also become a target for those who want to use his pain for their own gain. For example, someone might try to blackmail him or use his vulnerability to get access to secrets he knows. And if the scar hurting is a sign of a new threat, it could put all his friends and the entire wizarding world in danger again.
One challenge could be controlling the intensity. Lightning is a very powerful force, and it might be difficult for Harry to rein it in. He could accidentally cause too much destruction when he just wants to create a small spark.
Maybe he discovers it during a particularly intense storm at Hogwarts. He could be in a dangerous situation, like being chased by some dark creatures, and in a moment of desperation, he unknowingly summons lightning to protect himself.
There's no official information indicating that Harry Potter has read The Lightning Thief fanfiction. Harry Potter exists in his own fictional universe, and while fans might create crossovers in fanfiction, within the original canon, there's no such scenario.