Things weren’t always this way, long ago, before waves even began to touch the very edges of civilization, there was peace. Humanity had reached the highest heights of technology, and were pushing to climb even higher. They had achieved interstellar transportation at the speed of light, could alter the genes of animals to give them specific traits, they could even revive the dead. But even this was not enough to save them from the coming apocalypse. Although scientists predicted it long ago, the oceans were rising, high tide was getting higher and soon there was no low tide, just the ocean rising up as if to greet the toes of cities, and to reclaim what it once ruled.
With all of the great strides in technology, the world was able to hold out for little more than a few days, and soon fell under the waves. However, before the inevitable end of the world, the leaders of the five great nations, China, Russia, Japan, Australia, and Canada, were able to created underwater colonies, this is where primary remainder of the human species lives now. The rest live on floating colonies drifting unpredictably along the new ocean’s currents.
In an effort to preserve the majority of land animals, scientists dropped massive amounts of all types of radioactive substances into the habitats of living creatures, although some species went extinct, this was relatively successful, creating the merpeople and sea cows. However, it also led to the creation of some larger more aggressive entities to haunt the now deeper ocean.