Also known as Moon Shadows, it is a cult of Tsukiyomi that trains agents to deal with supernatural, mythical, and spiritual creatures that prey on humans. They have connections with the Yakuza, and work to protect the local culture and people, specially in the Nippontown district.
Its agents are trained both in the martial arts and spiritual teachings, mastering both body and mind. Some folks call them the "shadow side of Tsukiyomi", because of their shade dealings.
In their hierarchy, they have the agents, people who works in the field as a brute force and knows how to fight Denizens, and there are the moon priests and priestess, the people who knows how to appease the kami and are trained to deal with spirits. Usually the moon priests have roles of leadership within the organization.