Kero/Ceberus

Japanese Name: Cerberus
Dubbed Name: Kero
Nickname: Kero-chan
Birthdate: Secret
Favorite Foods: Anything sweet
Least Favorite Foods: Hot and spicy food
Favorite Pastime: Video Games
Favorite Colors: Red, orange
Favorite T.V. Shows: Quiz Shows
Favorite Flower: Sunflowers
Wish List: New video games

Kero is the guardian beast of the Book of Clow. While he does that, he falls asleep for 30 years. He is awakened by Sakura Kinomoto. Kero chooses her to become a cardcaptor because she appears to have magical powers since she is able to unseal the book. Kero-chan becomes his nickname because Sakura and Tomoyo name him that way. Sakura and he become close friends as the series progress.

Kero loves to eat and never seems to get full. He especially likes to eat sweets and pudding. But whenever Sakura is in danger, he tries his very best to save her from getting injured (setting aside the sweets of course). Kero often provides advices to Sakura by using his knowledge of the Clow Cards. Once Sakura captures the Firey and Earth card, he can transform into Cerberus, his true form,  since those two elemental cards are under his powers. Since Ceberus is a guardian, it is his job to protect his new master, Sakura, at all times.