In some fanfiction, it could be a test. Batman slaps Nightwing to see how he'll react under extreme stress. It's a way for Batman to gauge Nightwing's self - control and ability to stay focused even when physically and emotionally provoked. This could lead to Nightwing having to reevaluate his relationship with Batman and his place in their vigilante work.
Well, one possibility could be a story where Batman slaps Nightwing out of extreme frustration during a mission gone wrong. Maybe Nightwing made a critical error that endangered the entire Bat - family, and Batman's reaction was a slap in the heat of the moment.
Perhaps in a more complex fanfiction, there's a mind - control or false - memory situation. Batman slaps Nightwing, but later it's revealed that Batman was being manipulated by a villain. Nightwing then has to decide whether to forgive Batman or hold a grudge, while they both work together to figure out who was behind the mind - control and stop them from causing more chaos.
One idea could be that Nightwing is captured by a powerful new villain in Gotham. Batman has to use all his detective skills to find Nightwing's location. Then, in a intense showdown, he battles the villain's minions and finally rescues Nightwing. Maybe Nightwing was being held in an abandoned warehouse on the outskirts of the city.
One idea could be a story where Batman has to carry an injured Nightwing out of a dangerous situation, like a collapsing building during a fight with a powerful villain. It could show Batman's concern and determination to save his protege.
One idea could be a story where Nightwing has to take over Batman's duties temporarily in Gotham. He faces a new villain who is specifically targeting Batman's absence and Nightwing has to prove himself not just as a replacement, but as a hero in his own right.
One possible plotline could be Nightwing struggling to fill Batman's shoes in Gotham. He might face challenges like dealing with more dangerous villains who see him as a new target. Another could be his relationship with the other members of the Bat - family changing as he takes on the Batman mantle.
One interesting plot could be that they team up to take on a new and powerful villain in Gotham. Maybe this villain has some unique powers that force Batman and Nightwing to combine their skills in unexpected ways.
One possible plot could be that there's a misunderstanding. Maybe Batman has been mind - controlled and he hits Nightwing without realizing it. Nightwing then has to figure out how to break the control on Batman while also dealing with his own feelings of betrayal.
The power dynamic. Batman is the mentor, but Nightwing has grown into his own hero. Their sparring shows the shift in their relationship. It's exciting to see how Nightwing can now hold his own against Batman.
A great plot could involve Nightwing training a new generation of heroes in the 'Batman Beyond' universe. He could share his old - school combat techniques with the more tech - reliant heroes, leading to some interesting clashes and growth. For example, he might have a hard time getting used to the new gadgets while the younger heroes struggle with his more hands - on combat style. And together they have to face a villain who is exploiting their differences.
It can symbolize protection. Batman is the mentor, and when he carries Nightwing, it shows his instinct to keep Nightwing safe from harm, whether it's physical harm from villains or other threats.
A popular one is 'The Dark and the Light'. This fanfiction takes the uke Nightwing idea and runs with it. It shows how Nightwing's personality can be both strong and yet have a softer, more uke - like side when it comes to his relationship with Batman. The story also has great character development for both of them as they face different challenges together.