Lyssa Drak

Lyssa Drak is a DC comics supervillain associated primarily with its Green Lantern franchise, she is one of the Sinestro Corps and as such as a character that believes fear should be used to enforce strict totalitarian rule upon the universe, in opposition to the Green Lantern Corps, who believe in using will to safeguard the universe.

Lyssa Drak herself is in charge of updating and guarding a special tome known as the Book of Parallax and with it she holds knowledge on every important event and member in the history of the Sinestro Corps.

Her loyalty is unshakable in regards to Sinestro and her role seems to be eternally linked to the Book, which is physically strapped to her via a chain and requires her Ring in order to be translated properly.

Trivia

 * the Book of Parallax is named after (and presumably linked to) DC's personification of fear, Parallax.