Guinan

"The afterlife? No, child, but it is your afterlife. Welcome to the Knowledge Dimension. First one's on the house."

- Guinan to Sefer Yetzirah

Guinan was a Senior Archivist in the Knowledge Dimension who created a new version of Sefer Yetzirah to be one of their first canon agents.

History
In response to the increasing number of raids on the Knowledge Dimension during The Mazkertis Paradox arc, its Senior Archivists created the "Canonical Directive": a creed that stated that any information that was henceforth stolen from the dimension would be hunted down and extracted from the minds of whoever stole it, and that, if the stolen information had been used to make changes to any other reality or universe, those changes would be reverted by one of the Knowledge Dimension's to-be-appointed "canon agents" through careful, responsible manipulation of time. When the time came to select candidates for who would become the first canon agents, Guinan elected to create a new version of Sefer Yetzirah using the memories that the Knowledge Dimension's Archivists had extracted from the Reborn Universe's version of Sefer, due to her immense willpower and determination.

Guinan welcomed the new Sefer to the Knowledge Dimension by appearing in front of her at an empty bar and offering her a drink of Agresian ale, which Guinan had learned was RBU Sefer's favorite alcoholic drink. Although the new Sefer was aware that she had died, the rest of her implanted memories had yet to surface until she remembered that only Lilith knew what her favorite brand of ale was, which was a personal and private fact that this unfamiliar bartender could not possibly have known. When Sefer pursued this train of thought, the rest of her memories began to flood to the surface of her mind, causing a period of immense distress that Guinan guided her through. At Sefer's behest, Guinan explained that she was an artificial persona who had been constructed using the memories of RBU Sefer, who had died at the conclusion of the Sixth Arc Crusade, for a new and even greater purpose. Once the memory imprinting process had been completed, Guinan marvelled as the new Sefer unlocked her full potential, manifesting near-indestructible armor and advanced psychometric powers.

With a click of her fingers, Guinan then transported Sefer and herself to another area of the Knowledge Dimension that contained two infinitely long rows of plain white bookshelves. She retrieved one book that was inscribed with the words "The Canonical Directive - First Edition" which she handed to Sefer, but when Sefer opened the cover, Guinan teasingly slammed it shut, saying "That's homework. Your first lesson is a practical".

Trivia

 * The idea of Guinan being a member of the Knowledge Dimension who resurrects the Reborn Universe's Sefer in a new body to enforce the Canonical Directive was originally conceived by JS, who wrote a few pages in this story as part of the original plan for BZPB's 10th anniversary special (which ended up being replaced by a shorter story, Ten Years Gone, when the scope of the original plan grew too large and the writers ran out of time and motivation to finish it). Rather than let such a cool concept go to waste, however, Kon eventually incorporated some of what JS had written into Chapter 19 of The Mazkertis Paradox and expanded on his ideas there.