I'm not Inky, but don't think I can't be just as persuasive as you are. Did you really think I couldn't come up with a trade of equal, if not superior value?
TLW is probably someone who lives in Inky's head. TLW is probably aware he is not the original inhabitant in Inky's head, but Inky probably does not know about TLW. He just wonders sometimes who drank his milk and how ketchup ended up on his walls.