Now before I start this blog just wanna clear one thing up, not including Susan because, though she MAY be human, there is still a chance she might not be. Now to begin:
So, Finn is a unique character of the show due to the fact that humans are supposedly extinct. He could be one of the last humans if not THE last human. But I think Finn's uniqueness applies to Ooo, perhaps not the entire Earth.
A common theory about Finn is usually that his parents abandoned him, usually involving the ocean to explain his fear (perhaps even PTSD) of it. Now, let's use the somewhat common theory that Finn's parents were on a boat and left him to float at sea to wash up on shore. Who knows why they might do that. Perhaps they thought they would die and wanted humans to live on. So let's say in this situation that they DIDN'T die. What if they washed up on shore on one of the many other land masses. I don't think Ooo applies to the whole planet but simply one of the landmasses, hence the LAND of Ooo. So I think that Finn could very well be the last human in Ooo (unless Susan is human) but there might be a possibility of his parents or possibly other humans on the other land masses.
Share your thoughts.