Müllenkamp is a cult in Vagrant Story, headed by Sydney Losstarot. Its name is derived from an ancient dancer-priestess of Kiltia who based her activities in the cursed city of Leá Monde. Sydney took up the name when he created his cult based upon his own powers of the Dark.
Müllenkamp's enigmatic leader. He manipulates the cult and the faith of his followers to an unknown end, making him a villainous character. Using the power of "compulsion" he can control the minds of others.
The only other named member of Müllenkamp, Hardin is a friend of Sydney's, though he never shows much faith in the cult's beliefs. His real goal is the avenge the death of his little brother, and is using Müllenkamp as a way to get back at the government. He is Müllenkamp's second-in-command.
Müllenkamp (魔導師メレンカンプ, Madoushi Merenkanpu?, lit. Magician Müllenkamp) (given the first name of "Osana" in the French version, "Mellenkamp" in the German version) was a dancer and the head priestess of Ancient Kiltia. She founded the city of Leá Monde 2,000 years ago, gathering enough followers into her worship of the powers of the Dark. With the powers of the Dark she created Grimoires that hold within them powerful magicks. She bore with her the tattoo known as the Blood-Sin, which is the key to the powers of the Dark her city contained. This tattoo is carried over across her lineage, until it falls upon House Bardorba, particularly Sydney.
Using his ability to see inside people's minds, Sydney built a group of fanatical followers who offer him "body and soul." Though the cult is hated by the Order of the Crimson Blades, it survived due to the funding of the Duke Aldous Byron Bardorba. They are suspected of attempting to kill the king of Valendia the Yuletide.
In a surprise move, Sydney sends his followers to bite the very hand that fed them by attacking the Duke's home in the Graylands. Müllenkamp captures the Duke's family, and makes the pretext of two ransom demands: the freedom of their captive members and the abdication of Cardinal Batistum. The Crimson Blades attack, killing many of the sect's members. The attack seems a failure, though it captures the Duke's young son, Joshua. Sydney survives, and leads the Crimson Blades to the Müllenkamp base in Leá Monde. Müllenkamp's second-in-command, John Hardin, tries to convince Sydney to flee, but to no avail. The entire cult is destroyed in the battle, but they take the Crimson Blades with them. With the final destruction of Leá Monde, and the passing of the Blood-Sin tattoo to Ashley Riot, Müllenkamp fulfills its purpose envisioned by Sydney and his father, the Duke.