When Tyson first encounters Zeo, Zeo rescues him from a four-on-one fight with the Saint Shields. Zeo is much like any ordinary blader: inexperienced, somewhat lacking in confidence, and an enormous fan of Tyson. He quickly forms a strong friendship with the Bladebreakers. However, upon discovering that his father, Dr. Zagart, is the person seeking to steal the Bladebreakers' bit beasts, Zeo's father reveals a shocking truth: Zeo is a robotic duplicate of the real Zeo, who perished in an accident.
Zeo takes this revelation harshly and concludes he will never fit in with other kids, fearing rejection by Tyson and the others due to his robotic nature. Consequently, he declares them enemies. His father equips him with a formidable bit beast named Cerberus, stolen from a rock. Zeo intensively trains to master Cerberus and enters the tag team tournament alongside Gordo as his partner.
In the tournament, Zeo shocks everyone by decisively defeating Ozuma. Meanwhile, Kenny uncovers a peculiar anomaly during Zeo's battles. When Zeo faces Kai, he loses but manages to steal Dranzer. Tyson confronts Zeo, hoping to reconnect with the friend he once knew, but fails. In the final match, Zeo unexpectedly triumphs over Max by combining Cerberus's power with Dranzer, also stealing Draciel. This leads to a decisive battle between Tyson and Zeo. During their fight, part of Zeo's body malfunctions, revealing his mechanical nature to all. The battle concludes with Tyson victorious, and Dranzer and Draciel are freed. Encouraged by Tyson, Zeo learns to accept himself for who he is and ceases his pursuit of the Bladebreakers' bit beasts. Zeo was portrayed by Illich Guardiola.
