With the original Spanish title, Naschy had hoped to revive the success of LA NOCHE DE WALPUGIS. But since that film is not known outside of Spain by that title, a new one had to be sought. So CURSE OF THE DEVIL was one of the main ones used. Why that title and promotion? Well, at the time exorcism was big, as were satanic rituals associated with exorcism. In America, a push was made in ads to equate the film with THE EXORCIST and others like it.
For the first time, Naschy moved his Waldemar Daninsky character out of modern times and into a past decades earlier. The story is very pessimistic and somber.
For funding, Naschy had help and participation of Mexico. The two main actresses are Mexican, Fabiola Falcon and Maritza Olivares. The film was shown in Mexico as LA NOCHE DEL ASESINO!