Keroberos, commonly known as Kero-chan, is a key character in the anime series Cardcaptor Sakura. He is the Guardian Beast of the Seal, responsible for protecting the Clow Cards and guiding the protagonist, Sakura Kinomoto, in her quest to capture them. In his small, plush toy-like form, Kero-chan is cheerful, talkative, and fond of sweets, providing comic relief as well as valuable advice. His true form is a majestic lion-like creature with great magical power.