I

Enki Tasny, the 372nd Director of the Eme-an, also holds the title of the youngest director in its history.
As the oldest secret alliance, the Eme-an has long been the core of the Control Alliance of Visionary Eidos (C.A.V.E.), with its director seen as a symbol of the hidden facets of human history and the guiding figure for all secret alliances.
Unfortunately, Enki did not live up to the image that many expected. He set the record for the shortest tenure as the head of Eme-an—only 26 days and 14 hours. Within this short period, he only performed his director duties on the first and last days; the remaining time, he delegated his responsibilities to Ninsar, Nanna, or others. In short, it seemed Enki took the position solely to enjoy the conveniences and freedoms it offered without intending to fulfill the corresponding obligations.
Even those most dissatisfied with Enki's lackadaisical approach had to grudgingly admit that he was one of the era's most outstanding geniuses—though the "one of" qualifier was necessary due to the presence of his equally brilliant sister, Ninsar.

II

How does one become the Director of Eme-an?
Surprisingly, this question could fill a thick tome. Despite being an organization with nearly 400 generations and thousands of years of history, there is still no clear set of rules for appointing its head. Historically, each director's election has had different reasons; some were universally accepted, while others were contentious. Generally, as an ancient collective of scholars, Eme-an tends to select the era's most distinguished scholar as its director—even though these scholars often lack leadership qualities.
Enki is a quintessential example. He rose to the position of director because of a monograph—"The Map of the Babel Library: Manifolds, Probabilities, and Causality Arithmetics in High-Dimensional Expansions and Their Universal Representation Methods."
Of course, like Enki's other works, the title was added by the members of Eme-an who organized his extraordinary work. Enki's original title was "How to Avoid Nanna in the Library." After his 140th or 150th attempt to embark on an irreversible journey only to be dragged back by Nanna, Enki resolved that to elude Nanna, he had to discover all the pathways of the library, especially those unknown to her. He did not realize that this unintentionally provided the first theoretical framework for mapping the Babel Library.
Enki's algorithm could select the most likely path to reach a destination at every fork in the road. Although it was merely a slightly more probable choice among many possibilities, it was a significant encouragement for the members of Eme-an: They believed that the accumulation of tiny probabilities would eventually turn zero into one, opening the door to a room containing "truth."
Thus, Enki Tasny became the leader of truth-seekers.

III

Enki and the title of "the best Director of Eme-an" were worlds apart, separated by a gulf vast enough to fit a dozen Babel Towers. Instead, he earned the undisputed title of "the most elusive Director of Eme-an."
At the first C.A.V.E. leadership meeting after his appointment, Ninsar attended on his behalf, leading many from other secret alliances to mistakenly believe she was the new director of Eme-an. Enki's first act as director was to install "The Foolproof Door" in his office, a mechanism he had previously used to prevent Nanna from tracking him. As a result, during his brief tenure, most of his subordinates never had the chance to see what Enki looked like.\ However, "The Foolproof Door" did open voluntarily for one Eme-an member, marking the only time Enki personally invited someone into his office.
The invitee was Cosmos.
"My master is a genius, uninterested in understanding the thoughts of ordinary people," Cosmos later recalled with a helpless smile. "But that's only because he doesn't want to think about it. If he wanted to, he could see through my little thoughts in an instant... I thought I would spend my life following him, salvaging his groundbreaking inventions before he discarded them. I never expected that this minor talent would catch his attention."
As Cosmos described, he spent much of his career as a librarian following Enki around, uncovering the true significance of many of Enki's creations—at least, their significance from a common understanding.
This finally caught Enki's attention. Whatever Cosmos and Enki discussed after Cosmos crossed "The Foolproof Door" remains unknown, but from that day on, Cosmos began to refer to Enki as "Master"—despite being nearly 10 years older than Enki at the time.
Not long after, Enki "vanished" from the Babel Tower, leaving behind only a hastily written note on his desk:
"I, Enki Tasny, the 372nd Director of Eme-an and Head Librarian of the Babel Library, hereby recommend my apprentice Cosmos as the 373rd Director and Head Librarian."

IV

Enki and Ninsar's parents did not leave a significant mark in the long history of Eme-an. Aside from the surname "Tasny," they left no gifts for their children. Time has passed, and most of the Tasny generation has aged. Perhaps only Nanna retains memories of knowing them.
After giving birth to Enki and Ninsar in the library, their mother entrusted their father to bring them back.
Returning from the Journey of No Return is extremely rare, as most who wish to give up midway cannot find their way out of the library again. But Tasny managed to do so. He entrusted his two children to Nanna's care before quickly returning to his endless journey.
Nanna rarely mentioned that besides Enki, Ninsar, and their father, Sally also returned from the library. According to Tasny, without Sally, they could not have left the library.
After Tasny left again, Sally provided much comfort to Enki and Ninsar.
Eventually, Enki began to feel irritated; he did not want any creature constantly making noise around him, especially one that always circled around his legs on all fours, hindering his movements.
So, Enki began to meticulously study Sally in an unprecedented manner, trying to find a way to stop her from disturbing him, leaving behind a thick notebook. (Original title: "Suppressing the Activity of Small Juvenile Organisms," retitled by the librarians as "Sally's Observation Diary").
Some excerpts from the notebook are as follows:
"Sally has millions of hairs all over her body."
"In natural light, Sally's pupil diameter ranges from 2.5-4 millimeters."
"Sally is a warm-blooded animal."
"Sally resists having her nails trimmed."
"Sally feels safer curled up than when stretched out."
"Sally feels relaxed and happy when on all fours."
"Sally feels fear when away from me and Ninsar."