Retcon

Retcon is an abbreviation for "retroactive continuity", and refers to instances in fiction in which known facts are revealed to have actually been something entirely different all along. In general, a retcon does not refer to elaboration on a backstory (even when that changes the player's or reader's perspective on the subject), but to retroactive changes to concretely established facts. Instances of retcons in White Wolf fiction include:

• The revelations in Dirty Secrets of the Black Hand (that the Sabbat's Black Hand was secretly working for the True Black Hand all along, and that the Discipline of Vicissitude was actually a soul-eating alien parasite).
• The change in Necromancy (and, by association, Mortis) from a standard dot-based Discipline to a path- and ritual-based Discipline of blood magic.
• The revelation that the Gaki and Bushi clans were not Kindred but were instead factions of Kuei-jin.
• The revelation that the Laibon were not a bloodline but were actually a sect, one that used different Virtues instead of those of the Kindred; vampires created using the existing rules for Laibon characters are generally assumed to belong to the Akunanse Laibon legacy.
• The implication (made explicit by the author) that the wraiths Charon and Nhudri were actually named after a pair of Fallen, and that some of the historical deeds ascribed to the wraiths were instead committed by the two Fallen.