During the latter-end of the 19th century, Madame Zarkov was a Romani woman who worked as a proprietress at the Museum of the Weird, an establishment which held a collection of arcane and supernatural relics. She was an apparent advisor on the mystic in some regard for the Society of Explorers and Adventurers, namely to club-president Jason Chandler. Around 1880, Jason contacted Zarkov to assist fellow S.E.A.-member Barnabas T. Bullion who was encountering paranormal disasters in his mining-operation at Big Thunder Mountain. Due to the mountain being inhabited by a vengeful spirit, Zarkov advised Chandler to urge Bullion to abandon his mining.
By the 1930s, Madame Zarkov would become a member of the Adventurers Club. In 1937, Zarkov would attend a New Year's Eve party on Pleasure Island at the Adventurers Club base.
Madame Zarkov was a live-performed character created for the Adventurers Club of Walt Disney World. She would later be incorporated into Big Thunder Mountain Railroad at the Magic Kingdom with additional allusions to the Museum of the Weird and S.E.A.. The Museum of the Weird is an unbuilt attraction planned to be an extension of the Haunted Mansion in Disneyland's New Orleans Square which was developed by imagineer Rolly Crump. Zarkov's connection to the Mansion might be inspired by, "Madame Z", a character created by Marc Davis for the Haunted Mansion who later evolved into Madame Leota.
The Adventurers Club
Zarkov was an irregular character at the club who typically served as a replacement for regular-character Samantha Sterling. During the club's later performances they would both often appear in the attraction more regularly.
Big Thunder Mountain Railroad
In the queue for this attraction, Madame Zarkov is mentioned by Jason Chandler in a letter sent to Barnabas T. Bullion referring to the supernatural occurrences of Big Thunder Mountain.