• Master/Mistress: Sakura Kinomoto
• Birthday: Secret
• Symbol: Sun
• Attribute: Yang (Light)
• Eyes: Gold
• Body: Orange gold
• School of Sorcery: Western
• Favorite food: Sweet things
• Favorite thing: Lively & merry things
• Least favorite thing: Sad & lonely things
• False shape: An orange stuffed doll with white wings
• See also Kero

CLAMP picked the name "Cerberus." But Kerberos is closer to the nickname "Kero." Kero is the Guardian Beast (or Beast of Seal) of the book "The Clow." It duty is to watch over the Clow Cards to make sure they don't turn bad. However, it fell asleep... Without enough magic, Kero can't return to its true form, and stays like the shape of a stuffed animal until Sakura captures "The Earthy" and "The Firey." In Greek mythology, Cerberus, or Kerberos, is a three-headed dog with a serpent or dragon tail, which guards the entrance to the Underworld.