Librarian

"Each one of these souls is finite and precious.
 * And I'm close.
 * Close to saving them all."

- The Librarian

The Librarian was a Forerunner Lifeshaper, the highest rank a Lifeworker can achieve, and one of only three Forerunners to ever receive the title. She was married to the Didact, the Promethean supreme commander of the Forerunner military. During the Flood-Forerunner War, she led the Library Project, which sought to index all species in the galaxy and transport them to the Ark before the Flood could reach them or the rings were fired. Frequently clashing with her husband over the morality of the Array, the Librarian died at the end of the war when the rings were activated, willingly stranding herself on Earth within range of the Halo effect.

Research on Erde-Tyrene
"She comes to us when we're born. She watches over us as we grow, knows good and bad. She joys at our triumphs and sorrows at our passing. We all feel her presence."

- Chakas on the Librarian

She first met the Didact on Charum Hakkor before the human-Forerunner wars. Following the end of the war with humanity, she was permitted by the Ecumene Council to set up a research station on Earth (then known as "Erde-Tyrene"). Over the span of ten thousand years, she helped the human species, which had been devolved to a primitive state following the war, to slowly work toward re-creating a primitive society. The early humans worshiped the Librarian as a goddess-like figure, believing her to watch over all of the humans and come to each one at birth and assign them a purpose. In reality, she used an automatic imprinting system to transmit her geas into certain humans instead of physically visiting them. She believed that the mammalian-level intelligence exhibited by certain scyphozoa and cephalopoda on contemporary Erde-Tyrene were evidence of experimentation by the Precursors.

At one point after the Didact went into exile in a Cryptum, the Librarian devised a complex plan to bring her husband back. She imposed a geas on certain humans, causing multiple generations to attempt to pass the defenses surrounding the Cryptum. Finally, she used an ancilla to manipulate Bornstellar Makes Eternal Lasting, a Manipular, to go to Earth in search for treasure and open the Cryptum. While the original body of the Didact was apparently executed by Master Builder Faber some time afterward, he had performed a mutation to Bornstellar and thus imprinted Bornstellar with his consciousness.

At some point, the Librarian traveled to the San 'Shyuum world Janjur Qom to gather specimens of their species for storage. The Librarian's visit caused unrest among the San 'Shyuum, who began an uprising against the Forerunners soon after. The Librarian then traveled to Installation 00, where she later met with Bornstellar Makes Eternal Lasting, now in possession of the Didact's memories and personality.

Forerunner-Flood war
Before and during the Forerunner-Flood war, the Librarian traveled across the Milky Way galaxy at considerable risk to implement the Conservation Measure - the Lifeworkers' plan to protect all sentient beings from being absorbed into the Flood by sending them to the shelter of the Ark. She disregarded repeated pleas from the Didact to return to the safety of the Maginot Line, considering her work as being much more important than her own life.

The Librarian spent the last days of her life building, then deactivating and burying the portal on Earth leading to the Ark. The Librarian's destruction of the remaining Keyships left her stranded on Earth. The Librarian spent her last days near Mount Kilimanjaro, overlooking the Portal to the Ark.

Possible survival
343 Guilty Spark's logs from Installation 04, as well as communications logs from Installation 00, declare that the Librarian died as the Halo effect swept over Earth. However, sometime after the Human-Covenant War a duplicate of Guilty Spark had come to believe that the Librarian was still alive. This duplicate uploaded its personality construct array into an Office of Naval Intelligence vessel and set a course for the Librarian's apparent location.

Personality and traits
"I see very clearly how much the Librarian has shaped humanity since the end of the first human-Forerunner war. Whenever you look inward and see an ideal female… whether it be goddess, anima, mother, sister, or lover… For a brief, barely sensible instant, you will see the face and feel the spirit of the Librarian."

- 343 Guilty Spark

The Librarian cared greatly for all life. She held particularly deep respect for humanity, whom she viewed as "special" among all of the sentient life she had seen, and felt that it was well worth the sacrifice of her own life to save them. This was possibly due to the rare belief among Forerunners that humans were also molded in a similar manner to the Forerunners by the Precursors.

The Didact noted the Librarian to have a sense of humor unusual in Forerunners, which is why he suspected she had arranged such a complex plan to bring him out of his Cryptum and have two humans and a Manipular assist him in his quest.

The Librarian was said to have simple, yet elegant features, and her appearance was very youthful despite her age. She was considered beautiful by both humans and Forerunners alike. One effect of the geas she imprinted on humanity is that her image became what humans subconsciously view as the perfect female.

Title
It is important to note that "Librarian" would not have been her actual name or title. The Forerunner records of her transmissions utilize translation software so advanced that it incorporates idioms from the reader's own experience. Thus words such as "Eden", "fairy tale" and "Librarian" became the default usage in Forerunner terminals and transmissions when read by humans. This was likely because there is no direct translation for the original Forerunner words, thus the software utilizes human equivalents. These words appear in brackets in the Terminals. The same title is used in Halo: Cryptum, written from Forerunner perspective, though a note at the beginning of the novel mentions that all terms used are translated to understandable terms and phrases.

Trivia

 * The Librarian was first mentioned in Halo 3 in the terminals. In conversations, she is known as "L".
 * The Librarian's symbol seen in the terminals is also an emblem usable on Halo 3's Multiplayer.
 * The Librarian referred to the part of Earth she resided on as "Eden". This is a reference to the Garden of Eden in Abrahamic religions.
 * The Proto-Gravemind was originally called "The Librarian".

List of appearances

 * Halo: The Flood
 * Halo 3
 * Halo: Cryptum
 * Halo: Combat Evolved Anniversary
 * Terminals
 * Halo: Primordium
 * Halo: The Thursday War
 * Halo: Silentium
 * Halo 4