Clairvoyance (투시, in French clair meaning "clear" and voyance meaning "vision") is an ability that is used to expand the users' senses in different ways, such as to gain information about an object, people, or the location of an event through means other than that known by human senses, It is essentially an extra-sensory perception. This ability has only been used by Seira.
By having full concentration the user has the ability to expand their senses and also to the transfer of information that is both occurring to, or unaffecting, the clairvoyant. It is very different from telepathy in that the information is said to be gained directly from an external physical source, rather than being transferred from the mind of one individual to another.
In the battle between Frankenstein and Rael, Seira expands her senses' perception to search the area for humans to prevent causalities. She is the only known Noble, who uses this ability.