KEROBEROS OF CARDCAPTOR SAKURA

Cerberus (ケルベロス, Keruberosu?) is a fictional character in Clamp's manga and anime series Cardcaptor Sakura. His name is more commonly known in its romanized version, Kerberos, which is also often shortened to Kero-chan. He is voiced in his more common "hidden" form by Aya Hisakawa and Masaya Onosaka in his "true" form.
In the English adaptation Cardcaptors, he is known as Keroberos or Kero. He is voiced in the series by Matt Hill (borrowed form) and Richard Newman (true form), and in the second movie by Wendee Lee (borrowed form) and Dave Wittenberg (true form).
Kero also appears in the anime adaptation of Clamp's latest manga Tsubasa: Reservoir Chronicle. In Tsubasa Chronicle, Hisakawa Aya reprises her role (the one and only character from Cardcaptor Sakura to do so).


Name
Cerberus's name and form are based on Cerberus from Greek mythology, though the Greek monster has three heads.
Kero's name in Japanese is pronounced as "keh-ro". In Cardcaptors, his name is pronounced as "kee-ro" (such that it rhymes with zero).
The older TOKYOPOP releases of the manga render his name as "Keroberos," but this was changed in later printings to "Cerberus" at Clamp's request[citation needed].


Character and role
Cerberus is the Guardian of the Seal of the Clow who was napping at the time Sakura Kinomoto breaks the Seal and unleashes the Clow Cards. Cerberus is one of two guardians of the Clow (created by Clow Reed), and one of his missions is to select the candidate to become the new master of the Cards. The other guardian, Yue, is the Judge, who tests the chosen candidate on their ability to accept the role of master.
In his miniature, borrowed form he resembles an orange plush toy with white wings. Because Sakura feels that he does not resemble a "Kerberos," she calls him "Kero-chan." He initially rejects the name (Kero is also the Japanese onomatopoeia for the sound a frog makes, a comparison he resents), but soon comes to embrace it once he gets to know Sakura. Kero-chan is bossy, demanding, and gluttonous, but he also genuinely cares about Sakura and believes that she will become the next Master of the Clow, acting as her guide to gather the Cards. His hobbies include playing video games (which he takes up when he finds the console in Sakura's room and develops great skill at) and eating snacks and sweets, even though he receives his energy from the sun and does not need to eat to survive.
He has a particular fondness for cake, cookies, and chocolates. Even though he does not metabolize food, he is affected by alcohol (at one point becoming completely intoxicated after eating an entire box of chocolate liqueurs with no previous knowledge of their properties).
He also enjoys being filmed by Sakura's best friend, Tomoyo Daidouji and, unlike his Mistress, relishes the costume accessories he is asked to wear for these recordings. Even though he has been a willing servant all his life, Kero can be somewhat of an egomaniac, obsessing over his "coolness".

Cerberus's true form
Despite his behavior, Kero is remarkably intelligent. He is knowledgeable not only on the Clow Cards but also on all forms of mysticism, with a knack for reading magical auras. At one point this leads him astray when he mistook Kaho Mizuki for the false form of Yue because of her strong moon-aspected aura.
Cerberus often argues with Syaoran Li, who calls him "plush toy" or "stuffed animal" and whom he calls "kid" (小僧, kozō?) in the original Japanese) in return. This likely stems from Syaoran's initial arrogance and confidence that he will take over the Clow Cards, despite Cerberus's claims that Sakura is the actual Cardcaptor. Additionally, Meiling Li also takes a similar dislike for him, calling him a "bath sponge". While Syaoran is "kid," Cerberus calls Meiling "brat" (小娘, komusume?).
Cerberus's true form resembles a winged lion, but in order for him to achieve this original form, Sakura must capture The Firey and The Earthy cards. In his true form he has jurisdiction over all things fire and earth, the elements from which he draws his power. The known Clow Cards under his jurisdiction are Light, Firey and Earthy, but also quite probably the Glow, the Flower, the Little, the Shot, the Power, the Sweet, the Shield and the Sand. He can also raise powerful magical barriers, use his wings as a shield, and breathe fire.
Because The Clow had been in Osaka for a long time, Cerberus speaks in the Osaka dialect

credit: Wikipedia, The Free Encyclopedia