English singer from the "Devil-Music!" story of horror comic book Witchcraft #1 (Mar-Apr 1952). Her tale is part of the backstory-
"That boarded-up dressing room was last used by a famous singer, before your time...Mme. Santoro. One night we heard her scream! When we managed to get inside, no one was there! After that no one else would use the dressing room... and it was sealed up!" Turns out she made a deal with Satan for 25 years of fame. Satan was summoned by some magic sheet music. Just before the theatre is torn down, visiting singer-hopeful Helen Crane tours the theatre, gets in the dressing room and finds the sheet music.
Her first name is not given.