This is the first animated television appearance of the character of Winslow Schott, also known as the Toyman. The character was created by writer Don Cameron and artist Ed Dobrotka and first appeared in Action Comics #64 in September, 1943.
This is the first television appearance of Bruno Mannheim. He is also known as "Ugly" Mannheim in the series. Bruno Mannheim is the leader of Intergang with connections to Darkseid of Apokolips. The character was created by writer and artist Jack Kirby and first appeared in Superman's Pal, Jimmy Olsen #139 in July, 1971 in a story titled "The Guardian Fights Again!".