Kaijuu 2-gou was an Identified Kaiju and the second kaiju to ever recieve an I.D. number. After being killed by the Defense Force, it was converted into Isao Shinomiya's Numbers Weapon #2 before being eventually absorbed by Kaijuu Kyuu-gou.

According to Keiji Itami, Kaijuu 2-gou had an immense sense of pride, holding on to it until its very death.

In 1972, Kaijuu 2-gou attacked and nearly destroyed Sapporo, until it was defeated and killed by the Defense Force. Its corpse was then repurposed as the base for Isao Shinomiya's combat suit and gauntlets.