Spectral Contract (幽契約; yuu-keiyaku) is a family introduced in BS67, possessed exclusively by the Contract card, Petit Bat, and the Blood Crystal family cards with Contract Advent that support Petit Bat.
As Petit Bat is The PartnerKnight Bat's form after losing most of his power on Judgment Day, it adopts a new contract name. The name itself has a double meaning, one connects to how Bat is now in a specter-like form, and appears like Darkling; Another part is an alternate expression of "dark", which connects to how Bat is associated with the dark knights or some black rope knights in Camelot, and his old epithet, the DarkPurpleKnight (黒紫騎士).
Cards in the family are either Contract Advent forms of Petit Bat himself, or Spirits that Petit Bat got affiliated with while he was recovering in Camelot, or on his journey traveling around Lecoulis following Toa and the others.
