H.U.N.N.T.
H.U.N.N.T. or, Hunters Unfortunately Not Named on Tales is a voluntary vigilante group working to maintain peace in the Library World, formed by hunters who come and go when their narratives are taking place in many stories. Although they often fail to track down and stop Umbra's activities, they are usually responsible for the arrest of other petty criminals. Without them, the Library World would already have fallen into complete disarray.
H.U.N.N.T. has a sub-division taskforce called H.U.N.N.T.U.R. or, Hunters Unfortunately Not Named on Tales Umbra Response. It consists of Agents with special abilities put together to suppress the increase in Umbra activities after "the Anomaly".
Rambert works with H.U.N.N.T., but he's not part of H.U.N.N.T. Marina is part of the organization, despite her being a named character.