Any trait not listed on the standard DAV character sheet is a Secondary Ability and, as such, has a reduced cost to reflect its reduced usefulness. Secondary Abilities cost 1 freebie per dot at character creation. To buy the first dot of a Secondary Ability in play costs 2 XP and raising a Secondary Ability costs Current Rating x 1 XP. Examples of Secondary Abilities include Malkavian Time, Meditation, Fortune-Telling, Lores, Thanatology, Area Knowledge, etc.
The special Skill used for Vicissitude rolls is not a unique ability. Rather it is a Specialty of Crafts without which all Vicissitude rolls are made at +3 difficulty.
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