Castieo is seen in the episode Yamato vs. The Masked Marble, him being the masked marble. He first bumps into Yamato at the IBA Winners Tournament when Yamato is trying to sell lunches, he warns Yamato of his greatness and not to let it happen again. Castieo is last seen tying with Yamato for 16th place and is defeated by Yamato in an Ultimate Strike challenge. Castieo returns as Ike, hypnotized by Marda B into an evil man. After Ike is defeated by Yamato, Castieo returns to normal and gives Yamato a list of B-Da players that could be hypnotized by Marda B.
Castieo is a Hispanic B-Da Battler with a confusing accent and a cocky attitude. It is also shown that he is very muscular and a power built B-Da Battler with low control abilities. Castieo is actually very shy, telling Terry that he'd rather die than take of his mask. He named his custom B-Daman "Iron Eater".