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.
Well, in the fanfic, Bruce would probably become more withdrawn. He'd brood over Jason's death, questioning his methods and his role as a mentor. Dick would be angry at the world, especially at the villains who might have been involved. Tim, on the other hand, would be more determined to prove that he can be a worthy Robin, but also carry the pain of losing Jason. Alfred would be the one constant, trying to comfort everyone with his wisdom and care. It's a really tragic event for the Batfamily and their reactions would be complex and full of emotions.
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.
Well, in a 'batfamily meets reverse batfamily fanfiction', a lot of character development could occur. The members of the regular Batfamily would have to re - evaluate their own beliefs and methods when confronted with their opposites. Maybe they would start to question if there's a thin line between heroism and villainy. And the reverse Batfamily might also experience some changes, perhaps seeing a different path they could take from interacting with the 'good' Batfamily.
Some Avengers might be excited. Captain America, for example, would probably welcome Nightwing for his sense of justice and fighting skills. Thor might be intrigued by this new addition from another world (in a sense, as Gotham is different from Asgard). However, Hulk might not care much as long as Nightwing doesn't get in his way during a fight. Overall, there would be a mix of curiosity and acceptance.
I think Alfred from the regular Batfamily could be a really interesting character in this fanfiction. He's used to dealing with the Batfamily's heroics, but when faced with the reverse Batfamily, his loyalty and wisdom would be put to the test. He might try to find a way to reconcile the two groups or at least keep the regular Batfamily from being completely corrupted by the influence of the reverse Batfamily.
One of the best batfamily moments in fanfic is when they all come together for a family dinner. It shows their different personalities interacting in a normal, non - crime - fighting setting. Dick is cracking jokes, Jason is brooding but still participating, Tim is being the smart one with some tech talk, and Damian is reluctantly joining in. It gives a sense of family and normalcy that is often lacking in their vigilante lives.
The moment when the younger members of the batfamily look up to Bruce as a father figure is really heartwarming. In fanfic, it can be shown in small gestures like Bruce teaching them how to fix a car or cook. For Damian, it could be Bruce patiently guiding him through his emotions, which is a big step for Damian as he's not used to such emotional openness. It shows the family bond growing.
One popular 'batfamily fanfiction' story is 'A New Beginning'. It focuses on a young Robin adjusting to life in the Batfamily. Another is 'Family Bonds', which delves deep into the relationships between different members of the Batfamily like Batman, Nightwing, and Batgirl. And 'The Dark Knight's Heir' is also well - liked, where a new character emerges claiming to be Batman's heir, creating all sorts of chaos and revelations within the family.