A version of Earth where, as humanity has scaled up its ability to create and destroy, so too have the forces of nature. The testing of nuclear weapons has awakened and/or enhanced numerous forms of life that were previously unknown to, or perhaps just forgotten by, humanity. Now these giant monsters roam the planet, defending territory, fighting amongst themselves, or lashing out against the encroachments of humankind, who can do little but hope to be spared their wrath. Though a few of these 'Daikaiju' may have old allegiances to certain human communities, or connections to the supernatural. Humans have established a Monster Island project in the pacific ocean, a place where food and a pleasing environment are provided to the monsters, many of them residing there, in the hopes of studying, learning from, and placating the great beasts. Though there is little to keep them from leaving the island whenever they please.
Such vigorous activity and displays of power have drawn the attention of other eyes, as well. Numerous alien races hope to conquer or infiltrate this Earth for its resources, often bringing monsters of their own.
This theme covers the Godzilla universe extablished by the Toho movie studio. It is primarily based in the Showa era of movies (1950's-1970's), but as this era was never very particular about a coherent canon, influences from or monsters unique to other Godzilla eras are fully allowed. Since Toho now controls the property, this theme can also encompass the older Gamera films.