The first member of the militaristic nation of Digald to be encountered by Ruuji. He unintentionally damages the Generator at Ruuji's village and becomes a constant antagonist to him. Apparently suave and charming, he can also be ruthless in combat. Nonetheless, he prefers to conquer territories and cities rather than demolish them, in contrast to other Digald commanders such as Georg.

He was inducted into Digald when its forces attacked his village. In episode 24, he witnesses the pollution that Digald's industry has spread, and the suffering of former villagers. For most of the story, Zairin was portrayed as an obsessed Zoid pilot looking for a worthy challenge, and longed to face Ruuji in a fight to prove his worth.

Zairin had long suspected something was afoul with Digald, but it was not until he discovered that droid Digald pilots were actually human souls (including his long-time friend Whips) that he defected to join Ra-Kan's group. Ruuji and Zairin made peace with each other and cooperated in their campaign against Jiin. Zairin proved instrumental in the final battle, being the one to disable Jiin's bio particle cannon with a blast from his own. He was also the one who helped expose Bio-Tyranno's Zoid core, allowing Ruuji to strike it with Mugen Liger. After the defeat of Jiin, there was no epilogue to detail the fate of the characters so it's only speculated that Zairin probably went back to restore his village.

He pilots a MegaRaptor, a larger version of the Digald Bio-Raptor, with claws that can block metal Zi weapons. After he was defeated by Ruuji in Hayate Liger, Zairin was rescued and was given Bio-Volcano. In giving Zairin his Bio-Volcano, Jiin actually had a device that drained Zairin of his life energy. The device was eventually removed and Zairin was apprised of it.