Aurors and Ministry officials (supposedly)
Bringing down the Ministry of Magic
- "I don't think you should be an Auror, Harry. The Aurors are part of the Rotfang Conspiracy, I thought everyone knew that. They're working to bring down the Ministry of Magic from within using a combination of Dark Magic and gum disease."
- —Luna Lovegood at Professor Slughorn's Christmas party, on Harry's ambition to become an Auror.[src]
The Rotfang Conspiracy was believed, by Xenophilius Lovegood and his daughter Luna, to be a secret organisation within the Ministry. Supposedly, its members consist of Aurors and other high-ranking Ministry officials. Its main purpose is thought to be to bring down the Ministry of Magic through a combination of Dark Magic and gum disease.
Luna explained the conspiracy to Harry Potter, Horace Slughorn, Sybill Trelawney and Severus Snape at a Christmas party after Harry said that he wanted to become an Auror; Luna advised him not to because of the supposed conspiracy. This made Harry laugh so hard that mead came out of his nose. Only Trelawney was interested in this belief.
As most (if not all) of Xenophilius and Luna's beliefs are considered to be far-fetched by the wizarding world in general, the Conspiracy's existence is debatable.
It is worth noting, however, that Pius Thicknesse, head of the Magical Law Enforcement Department, was one of the key members of the 1997 Ministry of Magic Coup.
Rotfang could be a reference to bad dental health (i.e. Gum Disease)
- Harry Potter and the Half-Blood Prince (Mentioned only)