All of the main vampire characters, save for Colin Robinson, wear custom-made vampire fangs that clip into attachments on their teeth. This was done to ensure that traditional prosthetic fangs would not hinder their speech patterns or pronunciation of words.
Guillermo was originally supposed to be 20 years older. Harvey Guillén was the last of the main characters to be cast and was the wildcard due to him not being the age initially written for the character. He modelled himself after director Guillermo del Toro with round glasses and hair parted in the middle in order to make himself look older in his audition. He was cast just days before filming began.
The theme song, "You're Dead," was originally released in 1966. The artist who released it is Norma Tanega as part of her album entitled "Walkin' My Cat Named Dog"; the album's title track hit #22 on the charts.
Much like the original film, a lot of season one was shot outside. This quickly proved to be a logistical challenge as the series shot exteriors in Toronto in winter at night; temperatures on night shoots frequently hit below zero. When the series was picked up for a second season, the writers wrote more stories taking place entirely inside the house, and new interior sets were created so that less of the season would be shot outdoors.
During an interview with Collider, Kayvan Novak described getting the part of Nandor. "I auditioned in London, and it was just a scene. On the breakdown, it said, "You don't have to wear fangs, but if you want to wear fangs, then wear fangs." So, I went out and bought some fangs, I did my hair like Nandor does his hair in the show, and I wore a white shirt with the top button done up."