Inky Future

12,000 years in the future, in a world where mammals are mostly extinct and sea creatures have replaced them on land, the Inkling sibling duo Artemis and Orion (also known as Agents 5 & 6 of the New Squidbeak Splatoon), find a human laboratory being dug up by the Octarians in Octo Canyon. They are not remotely prepared for what they find.

Waking to a world he does not recognize, and a future without humanity, the robot known as 'X' has to find his own place in this new world, on top of finding himself already thrown into conflict.

Inky Future is a crossover fic between Mega Man X and Splatoon, with a scenario where humankind accidentally blew themselves up long before Dr. Cain ever was able to find X and create Reploids, and X is awoken by Inklings instead. Things get, well, interesting as a result.