Executive producer Greg Berlanti revealed the villain during a conversation following the Riverdale panel at the CW's Television Critics Association winter previews on Sunday morning. "We're finishing the script this weekend," he told a small group of reporters, confirming that the team has not yet started casting for the part.
Music Meister first appeared in the animated Batman series Batman: The Brave and the Bold, voiced by Neil Patrick Harris. He was bullied as a child for singing in choir, but then discovered he has mind control powers. He sends people to do his bidding after hypnotizing them with his high-pitched singing voice. He developed several music-based weapons and machines based on that power.
In the "Mayhem of the Music Meister" episode of Batman: The Brave and Bold, Music Meister falls for Black Canary until she rejects him due to her feelings for Batman.
Supergirl returns Monday Jan. 23 at 8/7c on the CW. The Flash returns Tuesday, Jan. 24 at 8/7c. The crossover episode hasn't been scheduled yet.
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