Roxy Brenner was a mobster who would often threaten business owners in order to get "Protection Money".
Brenner was created by legendary comic-duo Bill Finger and Bob Kane. He first appeared in Detective Comics #40 which also featured the debut of Basil Karlo (The 1st Clayface).
Major Story Arcs
The Murders of Clayface
Roxy Brenner "offers" Mr. Bentley protection money on the set of his new film but Bentley refuses to pay him. Furious, Brenner makes a shallow threat about injuring or killing one of the cast members. After Lorna Dane is murdered on the set, Brenner is considered a prime suspect. Wanting to "cash in" on the murder, Brenner suggested that he had killed Lorna in order to make Bentley pay him protection money. However, Batman and Robin beat Brenner and his gang and Brenner reveals that he didn't kill the actress.
The Coming of Clayface
In this retelling of "The Murders of Clayface", Brenner plays the same role as in the original. This time however, he suggests that he planned to kill one of the cast but wouldn't have done it for several days later. He is later arrested by The GCPD.