イストリア

The Head Librarian of the Great Library, Historia was created around the same time homo sapiens evolved the ability to tell stories from the imagination. Initially she executed her role alone as part of the "system" governing the maintenance of the collective gestalt that is the world of stories, but repeated interaction with the characters in stories and the occasional human guest Librarian allowed her to develop human emotions and a personality.

Historia has the important role of coalescing stories in their published form from the wellspring of human imagination into books for the Great Library. In addition, she can give form to the fragments of imagination which have not yet been published as stories and materialise them in the Great Library. In this way, she can literally summon food from thin air and obtain the latest entertainment devices from the human world.

 When Shiori is summoned as a Librarian, Historia has recently become acquainted with the new gamut of human emotions but is unsure how to understand them. At Shiori's urging, she endeavours to write her own story which will allow her to understand and cope with human emotions better. Unfortunately her story does not take off and the Register she created, Iris, eventually fades from her consciousness and is presumably destroyed by the worms.

When Iris and Historia reunite again after the former was thought lost to oblivion, the latter almost succeeds in killing her daughter were it not for the intervention of Eito, Tale and Shiori. After reconciliation, Historia rewards Eito and Shiori for their contributions by making an exception for the pair with regards to their Colletes which are normally returned to the Great Library before humans are sent back. /