Deadman says that Batman previously helped him solve his own murder; although this is Deadman's first appearance in a DCAU series, he appeared in issues of the animated continuity-based comic books, "Batman & Robin Adventures" #15 and "Batman: Gotham Adventures" #6 based on Batman: The Animated Series (1992) and The New Batman Adventures (1997). The story in "Batman: Gotham Adventures" #6 is what Deadman is referencing in this episode.
The first on-screen appearance of the DC Comics superhero, Deadman.
Michael Beach voices Devil Ray which is based on the character of Manta Ray. Coincidentally, he also plays Manta Ray's father in the feature film Aquaman with Jason Momoa.
Michael Rosenbaum, who plays the Flash in this series, played Deadman in "Dawn of the Dead Man! (2009)".