Yamada is an officer in Spirits, the international organization that deploys the giant robot Devadasy against alien threats. He participates in command decisions during operational crises. When Devadasy became infected and released an alien parasite, Yamada was involved in the critical choice to self-destruct the evacuated Spirits base. This action successfully interrupted the alien absorption process but unintentionally enabled the parasite to harness the explosion's energy, transforming it into a hostile mecha form.

No concrete information exists regarding Yamada's physical appearance, personal history prior to joining Spirits, specific rank progression within the organization, or expanded universe appearances in other official media beyond the original OVA.