Twilight Lady is a villain mentioned in Watchmen who appears in the second part of the game Watchmen: The End is Nigh. She is a BDSM–themed criminal and "Vice–Queen" who runs illegal sex–based industries and has kidnapped people as sex slaves. Nite Owl had a Catwoman–esque relationship many years ago, and she actually sent him a signed picture of herself at one point which he still has (this is how she is brought up in the original comic).
In the game, which takes place in 1977 after Rorschach has officially gone insane, Twilight Lady is seen in a porn film dominating a known missing girl, and Nite Owl and Rorschach go to her hideout to investigate, where it is eventually discovered that the missing girl willingly ran away to be a sex slave.
When Twilight Lady is fought and defeated, she is left lying on the cracked glass roof of her building at a deadly height, and Rorschach insists on killing her, due to his general brutality and particular hatred of abusers of youth, due to his traumatic previous encounters with them. This leads to a physical fight between him and Nite Owl, where the winner is whichever one you are playing as. If Rorschach wins, he shoots Twilight Lady and she falls to her death, which makes Nite Owl very upset, while if Nite Owl wins Rorschach falls but survives, and when Twilight Lady tries to flirt with Dan, but he lashes out at her and tells her to leave the city or he will kill her himself.