Reversed Ancient is a language from the Second Era in which some of the old scrolls stored in the library of Brigobaen were written. Cecil and Beleth are among the few people who can still decipher it, however, they need to use a special golden mirror to do it. The mirror, allegedly crafted from the Curio, has been lost or stollen during the liberation of Marali from the Twins in 426, and has never been recovered.
The two main known texts written in Reversed Ancient are the formerly missing pages of Neth's journal (father Cecil could not know why were those not written in common as the rest of the volume), and the mouldy book. According to Cecil, Reversed Ancient is richer than common in the vocabulary of emotions.