Originating as the personification of a decommissioned Imperial Japanese Navy destroyer reborn as a breakwater at Onahama Port after World War II, the character safeguards the coastline against extradimensional invaders emerging from a seismic rift triggered by the 2011 Tōhoku earthquake. When threats arise, it awakens as a mechanized combat unit, channeling the original destroyer’s armaments, strategic design, and maritime resilience. Tasked with defending the port, it joins forces with a fellow sentient warship and a human coalition—including a resourceful local cyclist—to neutralize interdimensional breaches. The narrative intertwines the vessel’s historical legacy as a wartime protector with its new role in a science fiction conflict, anchoring its purpose in repelling cosmic threats while preserving Onahama’s fragile peace.