He might try to reason with kaldur. If Nightwing can make kaldur see that what he's doing is wrong or that there are better ways to achieve his goals, kaldur could let him go. Nightwing is known for his charisma and intelligence in such situations.
He might try to engage Slade in conversation. Nightwing is smart and could be looking for a way to psychologically get an edge over Slade. He could be probing for Slade's motives, hoping to find a way to turn the situation around. He might also be stalling for time, waiting for the right moment to make his move.
Batman is the most likely. He has a strong bond with Nightwing and would do anything to save him. His skills in combat and detective work would be crucial in finding and freeing Nightwing.
Nightwing would initially be defiant. He's a highly trained fighter and detective in his own right. So, he won't cower in front of the Joker. He'll probably try to size up the situation, looking for any weaknesses in his captivity and the Joker's plan.
Batman could be a main character. Since Nightwing was trained by Batman, in a baby Nightwing fanfiction, Batman could be the one taking care of him, teaching him basic skills, and protecting him from the threats of Gotham.
Captain America could be a strong ally for Nightwing. Captain America is a great leader and has a strong sense of justice. Nightwing, coming from Gotham, also has a deep - rooted sense of right and wrong. They could lead the Avengers together in a battle, with Captain America providing the strategic leadership and Nightwing using his agility and combat skills to execute the plans on the ground.
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.
One idea could be that Nightwing is transported to the Avengers' universe through some sort of interdimensional rift. He then has to team up with the Avengers to fight a common enemy, like Thanos who has somehow acquired some of Batman's tech. Nightwing's acrobatic skills and detective abilities would be a great addition to the Avengers' power set.
First, know Nightwing's character well. Read the comics and other official materials. Then, come up with a unique plot. For example, you could put him in a new location or situation. Also, focus on his relationships, like with Batman or the other Titans. And don't forget to add some action scenes to keep it exciting.
There are several amazing 'nightwing fanfiction' out there. For example, 'Nightwing: Shadows of Gotham' is a story that focuses on Nightwing's adventures in the darker parts of Gotham. It has great action scenes and a deep exploration of his moral compass. 'The Nightwing Chronicles' is also a popular one, which chronicles his day - to - day life as a hero, with some really cool character development. 'Beyond the Mask of Nightwing' is a story that shows what lies beneath his heroic facade, with a very engaging plot.