Clow appointed Kero as the one to select the potential candidate to be the next master of the cards, Cerberus himself, and his "brother" and fellow guardian, Yue. After Sakura accidentally releases the cards, Cerberus chooses her to be the candidate and teaches her the basics of capturing the cards. Throughout the series, he displays an extensive knowledge of mysticism. After Sakura passes the Final Judgment to become the Clow Cards master, Cerberus remains with her as a friend, companion, adviser, and protector when new threats appear. Having spent a lengthy amount of time in the book while it was in Osaka, Cerberus speaks with a pointed Osakan-accent. He tends to be bossy, demanding, egotistical and gluttonous, but clearly displays his affection for Sakura, especially if she is hurt or in danger. He becomes very fond of video games, and is addicted to sweets. Cerberus spends most of his time in a "temporary" or "false form": a small figure resembling an orange stuffed animal with wings. Unlike Yue, Cerberus' magical powers are like the sun, and thus largely self-sustaining, and he is subsequently not as dependent on his master's power to support his life as is Yue. However, his master must have control of the Firey and Earthy cards in order to power his true form, a large-winged mountain lion. In the anime adaptation, the Light card is changed to the Earthy card to delay his obtaining his true form. Cerberus' name is taken from the Greek mythological figure, Cerberus, a large three-headed dog who was assigned to guard the gates of the Greek underworld. In the bilingual Kodansha version of the manga, the name for Cerberus' borrowed form is Cero. In the anime adaptation, his false form is voiced by Aya Hisakawa, while his hidden form is voiced by Masaya Onosaka. In the Animax dub, his false form is voiced by Sarah Hauser, whereas his true form is voiced by Darren Pleavin. In the Cardcaptors dub, his name is spelled Keroberos (based on the Japanese pronunciation of his name), and "Kero" was repronounced as "kirō" instead of "kerō". In this dub, his false form is voiced by Matt Hill with a New York accent, and Richard Newman voices his true form, though the accent is not as distinct. In the second film, he is voiced by Wendee Lee and Dave Wittenberg, in his respective forms. In the English dub