Goichi Shima is the chief mechanic at the Shinkansen Ultra Evolution Institute's Yokokawa Branch, overseeing maintenance, manufacturing, servicing, and development for the Shinkalion Z robots. Affectionately known as "Oyassan" by colleagues, this nickname reflects his veteran status and leadership within the maintenance team.

He maintains a long-standing professional relationship with Abuto Usui, a young genius mechanic involved in Zailiner research. His direct subordinates include mechanics Atsuta Hosokawa and Abuto Usui, while Tokonami Usui is noted as a former superior.

Physically, Shima has brown hair styled in a chest-length ponytail, a goatee, and black eyes. His standard work attire consists of a jumpsuit and gloves.

The character's name holds railway engineering significance: "Goichi" likely originates from "Degoichi," the nickname for the JNR Class D51 steam locomotive, and his surname "Shima" honors Hideo Shima, the Japanese engineer who led the original Shinkansen's development.