- Nailers was not the group's original name, which was not revealed. They were not known by this appellation until the human calling himself Heinrich Kramer became their public leader.
They were originally a pacifist group -- formed following Earth's first contact with the Vulcans in 2063 -- that advocated focusing more on Earth and the Sol system rather than the exploration and colonization of interstellar space. (Absolute Horizon, "Following Shackleton")
Membership in the organization was signified by the wearing of a tattoo of a hammer. This tattoo was, in actuality, a telepathic transceiver that enhanced Kramer's control over his followers. (Absolute Horizon)