The Green Laterns that arrive to deal with Amazo include: Arisia, Chaselon, K'ryssma, Katma Tui, Kilowog, Larvox, Palaqua, Kyle Rayner, Salakk, Spol, Stel, and Tomar Re.
Luthor's hideout being located underneath a barbershop was based on the same system used by a Marvel Comics character, Nick Fury who ran S.H.I.E.L.D. headquarters.
According to the commentary, the Cadmus plot had been finalized well before Lex Luthor's role in this story had been finished, though it aired sooner.
The Atom/Dr. Ray Palmer makes his first full appearance in the DCAU in this episode. Ray Palmer was first mentioned in Justice League (2001) at the end of Hereafter: Part II (2003) when Vandal Savage begged Superman to stop his past self from stealing a "white dwarf-powered" device from Palmer. After that Palmer was first seen on screen in a cameo appearance sitting on Wonder Woman's shoulder in Initiation (2004) listening to the initiation speech by Superman.
This episode features a full appearance by Green Lantern Kyle Rayner, his first full animated appearance in the DCAU since his debut in Initiation (2004) on Superman: The Animated Series (1996) and voiced by Michael P. Greco. Kyle is still stationed on OA as mentioned in Hearts and Minds: Part II (2003) on Justice League (2001) as John Stewart is the active Green Lantern of sector 2814 on duty. In this series, Kyle's similarities with Hal Jordan begin to fade and he now closer resembles his comic counterpart wearing an animated adaptation of his comic uniform at the time of production. He is also now voiced by Will Friedle.