Ruuji is the protagonist of Zoids Genesis. An inhabitant of the seaside Mirodo village, who recently excavated the Murasame Liger when a group of Bio Raptor zoids attacked. In a fight between Zairin and Ruuji, Zairin damaged the generator (a tree-like structure that maintains the environment around the village). With Ra-Kan and Mii, he sets of to find a mechanic who can repair the generator. He has a younger brother, and was given a telescope by his father for his journey.

During his quest to find a generator mechanic Ruuji becomes embroiled in a struggle against the expansionist nation of Digald. He realizes repairing his village generator won't mean anything without peace and he suggests to Ra-Kan an organized stand against Digald.

Having lived in the village his entire life, he is somewhat naïve, but also determined and possessing a strong sense of justice. His unwillingness to allow those he encounters to suffer often puts him in over his head, as well as his traveling companions. Ruuji at one point tried to free people from Digald forces, but that action almost led to the destruction of his team when Georg launched a surprise attack. However, his mistakes gave him a better understanding of approaching things and allowed him to become a wiser person and competent zoid pilot. He's constantly under training from Seijurou to help him become stronger.

Ruuji would eventually became the star hope against Digald. As a skillful pilot, he and Murasame Liger's reputation grew into a continental sensation as a liberator and savior. While various people within the suppression army doubted him, he won over their confidence in battle and showing his tactical ingenuity. He would eventually lead his own division and temporarily became leader of the Ra-Kan's army. The leading group members all knew Ruuji and his competence and didn't object to his young leadership. He also won the confidence of the people of Sora Sky City. The colors of his Zoid scheme became official flag in the army as well. Eventually Ruuji and most of Digald forces became partners in fighting against Jiin and renamed themselves as Jiin Suppression Army. Ruuji, in the end, was the one that gave the finishing blow that destroyed BioTyranno and Jiin. After winning the war he returned to his village, but there was no epilogue to tell what happened, as the ending only shows Ruuji's return home, it also shows the solution to restore the village was Murasame Liger itself used as a core for the generator. It can be assumed he followed his in dream in becoming a typical man in his village as a teacher.