While most of Batman's romantic relationships tend to be short in duration, Catwoman has been his most enduring romance throughout the years. The attraction between Batman and Catwoman, whose real name is Selina Kyle, is present in nearly every version and medium in which the characters appear. Although Catwoman is typically portrayed as a villain, Batman and Catwoman have worked together in achieving common goals and are usually depicted as having a romantic connection.
In Batman: Arkham City, although their love is not explored, Catwoman constantly flirts with the Dark Knight whenever they meet. Catwoman even gives up her sure escape from Arkham City to go back and help the injured Batman. A hidden radio reel reveals that Catwoman has a slight grudge towards Batman, though, since he knows her secret identity but she doesn't know his. However, by the time of the events of Batman: Arkham Knight, Selina is aware of Batman's identity as Bruce Wayne, addressing him as such after he rescues her from the Riddler.
Joker hosts a mock dinner in the caves leading to the Batcave. Alongside a bound Batman, his allies are also bound at the table with their faces bandaged, and Batman is warned that escaping will agitate flints and ignite his gasoline-doused allies. Alfred, who has been gassed by the Joker, serves all but Batman with a cloche containing their severed faces. When Joker threatens to ignite the gasoline himself, Batman escapes and triggers a blaze, but uses an explosive and his knowledge of the cave system to blow open the cave roof, allowing water to rush in from above and douse the flames. Batman pursues Joker to the edge of a large drop. Batman claims that he knows Joker's true identity, but to prevent him from saying it, Joker purposefully knocks himself over the edge and falls out of sight. Batman reads Joker's book which he claimed contained the real identities of the Bat-family but it is blank. Meanwhile, the Bat-family are gassed and attack each other but manage to fight off the gas's influence. Later, in Wayne Manor, Batman tells a recovering Alfred that after finding the joker playing card in the cave, he confronted Joker about it in Arkham Asylum as Bruce Wayne. Joker failed to acknowledge him and Batman realized that he did not care who Batman was under his mask. In the present, Batman receives excuses from the Bat-family for them not coming to meet with him. Later, Batman studies the chemical makeup of the gas Joker used on the Bat-family and finds an inert isotope; the chemical compound "Ha".
Batman is often treated as a vigilante by other characters in his stories. Frank Miller views the character as "a dionysian figure, a force for anarchy that imposes an individual order". Dressed as a bat, Batman deliberately cultivates a frightening persona in order to aid him in crime-fighting, a fear that originates from the criminals' own guilty conscience. Miller is often credited with reintroducing anti-heroic traits into Batman's characterization, such as his brooding personality, willingness to use violence and torture, and increasingly alienated behavior. Batman, shortly a year after his debut and the introduction of Robin, was changed in 1940 after DC editor Whitney Ellsworth felt the character would be tainted by his lethal methods and DC established their own ethical code, subsequently he was retconned as having a stringent moral code. Miller's Batman was closer to the original pre-Robin version, who was willing to kill criminals if necessary.