Wow. A living, anthropomorphic piano has already ruined planet Turo and Earth is next in "The Dance of Death" story of comic book Rocket Kelly
#4 (Aug-Sep 1946). He can play music that forces people to dance against their will until they die. Hero Rocket Kelly and his sidekicks Diana and Punchy fly to planet Turo and save the day. Comic-relief Punchy is immune to the music because he's tone-deaf. He helps them escape and they fly after the invasion force and defeat it.
The only backstory the Minstrel mentions is he was banished for some unstated reason, and thence plotted his revenge.
His minions are all different anthropomorphic musical instruments- all unnamed and only briefly shown.