Splatoon: The Colors Of Life

Chapter 0: Prologue (World of Splatoon)

The twilight years of human history had been difficult ones, marked by no fewer than five world wars and countless lesser conflicts. During the last of these world wars, a nuclear warhead hit the South Pole. The resulting atomic fireball melted the Antarctic ice cap, causing sea levels that had already risen to dangerous levels from years of global warming to reach catastrophic levels. Despite the attempts of a handful of survivors to hide away from the ensuing flood in underground cities or enter cryogenic stasis in the hope that they could reclaim their world, mankind soon went extinct.

After about 10,000 years however, the water levels began to recede, forcing many sea creatures to evolve into intelligent, humanoid land-dwellers. Upon reaching this point, these evolved species began rapidly progressing, experiencing various periods similar to humanity's own progression, but in a more compressed amount of time as a result of their discovery and reverse-engineering of human technology.

There were amicable relations between the Inklings and the Octarians. As time progressed, the Octarians separated themselves from the other species of the Mollusc Era. They became dissatisfied with the amount of available dry land and waged war on the Inklings, the other dominant species at the time, to gain total control of the turf. The Octarians constructed a variety of large machines known as the Great Octoweapons and began attacking Inkling cities. However, due to one of the Octoweapons' plugs being pulled, the Inklings secured a victory in the war and forced the Octarians to retreat to underground lairs such as Octo Valley, which were constructed from the ruins of the subterranean cities built by the remnants of humanity.

This is when Inkopolis city was built and the tale of a Blue Inkling Boy named "Lai" has begun.

And yeah, here's the opening of this story..