Yes, Batman did kill in The Dark Knight Returns comics in some instances, but it was within a specific context and for particular reasons related to the storyline.
Well, in this story, Batman is the star. He is the Dark Knight returning to clean up Gotham. Alfred, his butler, is an important character as he is always there to support Batman, whether it's with advice or helping with his gadgets. And then there's Carrie Kelley who becomes the new Robin. She adds a new dimension to Batman's story with her youth and enthusiasm.
One of the main themes is the concept of an aging hero. Batman is older but still feels the need to fight crime. Another theme is the idea of a dark and gritty Gotham. It shows that the city is full of chaos and corruption that Batman tries to combat.
The main characters in the batman dark knight returns story include Batman, who is the protagonist coming out of retirement. Commissioner Gordon, his long - time friend and ally in the fight against crime in Gotham. Carrie Kelley, the young and feisty girl who becomes Robin. The mutant gang leader, who leads his gang in causing havoc and is a formidable foe for Batman. Additionally, there are characters in the media and in the political arena who play roles in either supporting or opposing Batman's return to vigilantism, all of which contribute to the rich tapestry of the story.
The main plot is about an older Batman coming out of retirement in a Gotham that has deteriorated. He has to face new threats like the mutant gang and also deal with the changing political and social climate that is both against and in need of his brand of justice.
In this novel, Batman is front and center. He's the aging hero trying to reclaim his city. Commissioner Gordon, his old ally, is a key figure. The Joker, as always, is a major character, bringing his brand of madness. And we can't forget about Harvey Dent, Two - Face, who adds to the complexity of Gotham's criminal underworld. There's also Carrie Kelley, a young girl who becomes Robin and provides a different perspective.
One of the main themes is the idea of an aging hero. Batman is older but still feels the need to fight crime in a Gotham that has changed. Another theme is the blurring of the line between hero and vigilante. His extreme methods raise questions about justice. Also, the corruption in Gotham and society's reaction to Batman's return are important themes.
One idea could be exploring the backstory of a minor character from the original. For example, the street thugs that Batman encounters. What led them to a life of crime? Another could be a time - travel fanfic where Batman is sent to an alternate future or past Gotham. Maybe he has to deal with a version of himself that has gone too far in his methods.