JIKO (ジーコ) o también conocido como Zico, es un hombre de 79 años de edad y es uno de los seis sabios de Templar ; Él tiene una personalidad bastante tranquila y sabia. Zico es el maestro de la Roya , una niña de noble cuna que había salvado, cuando era un niño. Después llega Zed, Zico actúa como su mentor, y le da consejos en muchas ocasiones. A lo largo de la serie, Zico rara vez deja de Templar, pero permanece para regular su política y autoridad. Zico también le dice a Zed para proteger Roya y para mantener una estrecha vigilancia sobre su bienestar. Zico jugó un papel muy importante en afectar Kiba y su vida
Zico possesses a very strong Spirit (due to his own strong will) called Pryon that seems to want to be captured by the military of Zymot. His Spirit is on a power level with Rambos (Zed's second Spirit). Zico's Spirit is a large red dragon that has many curves on its body, in which it regularly breathes large amounts of fire to completely destroy its opponents.
Zico often stresses caution and observation over rash action, and is quick to provide 'fatherly' advise to both Roya and Zed when they are experiencing periods of doubt. He was a friend of Neotopia's ruler, Hyrum, and was distressed to see how Hyrum had transformed Neotopia into a harsh state. Conversations between the two seemed to reveal that once Hyrum was much like Zico, but had become radical later in life.
Recent events have revealed that Zico was not always the kind and patient man he is now. Revelations about Zico's past have surfaced recently since the appearance of Zed's mother, Sara. It became obvious that Sara hated Zico, and Zico was hiding something that was of great pain to him. Zico later revealed to Zed that Amil Gaoul had once been the guardian Spirit of Templar but no one could wield him, not even Zico. To ensure Templar's survival, Zico had begun an aggressive campaign to find a Shard Caster for the key Spirit. This appears to have gone on for some time until Zico discovered that Amir Gaul had chosen someone else. Zico had been shown a vision of Zed's young mother, pregnant with Zed.
Zico traveled to Calm and abducted Zed's mother, Sara, and took her back to Templar where she was forcefully turned into a Shard Caster and received Amil Gaoul's shard. Zico then rigorously trained Sara to one day wield the Spirit, often working Sara so hard she would collapse at night from fatigue and pain. Later, Zico defended Templar from an invasion by Zymot. It was during this battle that Sara tried to call out Amir Gaul, and when he appeared he abandoned Sara and left. Realizing that Sara was not the chosen one, Zico turned his back on Sara and told her to return to Calm.
After meeting Zed, Zico came to the realization that he had made a mistake thinking Sara was the chosen vessel of Amir Gaul. It was not Sara who was chosen, but her unborn child, Zed, growing in her womb, who was the chosen one. When Zed attempts to follow his mother, Zico intervenes and blocks his path. After exchanging angry words, he and Zed battle each other, and Zico knocks Zed unconscious with a swift blow to the gut. He then locks Zed up in a cell. After Zed awakens, Zico tries to explain that Sara has been possessed by the 'demon' within Amir Gaul. As he was responsible for making her a Shard Caster, it is his responsibility to stop her rampage.
Zico sets out on Pyron searching for Sara and finds her some time later in the act of absorbing more life force energy. A battle ensues and Zico's Spirit soon faces off against Sara's Key Spirits, Menadi and Pronimo. However, Pyron is able to not only withstand the two key Spirits, but push them back. Zico explains to the stunned Sara that she could never control a key Spirit, and as such she can't truly bring out Menadi and Pronimo's power. Just as he begins to gain the upper hand, Sagiri appears and Sara grabs the little girl to use as a human shield. Unable to attack, Zico can only defend against Sara's merciless shard attacks. Eventually Zico is overpowered and collapses.
Some time after, Zed leaves with the Seekers, Zico and the other sages of Templar sense a power surge from Tusk. Believing it has something to do with Zed, Zico leaves to investigate. Roya confronts him and convinces him to let her go along. They fly to Tusk on Pyron and begin searching for him. As they separate, Roya is attacked by Sara, but Zico repels her attacks. Sara attempts to fight, but is so weak she can't even cast a shard. Zico tells her that in her condition, trying to wield Amir Gaul would be fatal. Sara comments that she doesn't care and flees.
Zico and Roya then locate Zed and learn about the events surrounding Noah, Mirred, and the strange black Spirit. Shortly afterward, Zed goes off with his mother, Sara. Later, Sara re-emerges with Amil Gaoul's shard and Zico confronts her demanding the return of the key Spirit. Sara summons Amil Gaoul and battles Zico and Pyron. His Spirit is no match for Amir Gaul and Zico collapses to his knees. Before Sara can finish the fight, however, her body is overcome by the stress of wielding Amir Gaul and collapses. Roya arrives and holds Sara as she dies. Zico can only look on in sorrow, unable to help her.
During Noah and Zed's final battle, he ordered Roya not to interfere with their battle. It's revealed that he, too, wanted to see Tusker resurrected. Unfortunately, he was horrified over the fact that the power he sought was destroying the world. When Tusker merges with Zed, and Tusker controls all the Spirits, he saves Roya from Afkeruru, but subsequently dies in the process. He then appears as a Spirit within Tusker to talk with Zed. He ultimately persuaded Zed to come to his senses when he reminded him of how his mother ended up dead after seeking power. Zico is never heard from again.