Sci Fi Sea Story

When you come up with a story just to dump some ocs in and walk away.

200 years ago, humans started polluting the seas with various trash that killed many sea creatures which greatly upset the guardians of the ocean. At the same time, global warming was rising the sea levels to a very concerning degree, and oh boy was that used for their full advantage! Boats kept sinking for no reason. Lots of people begane going missing and various marine life kept growing more than they should be able to, and cities kept flooding to the point where they became uninhabitable. This lasted for ~70 years until the humans gave up and went into hiding, leading the now new human-sea creature hybrids to take over and rebuild the world as we know it!

However, this history has long been forgotten and some very peculiar individuals are trying to figure out the history of the previous world.