That's the name given to all final saves, so far as I know. It's almost a complete game save; it saves right before the final dialogue where you choose what to do with the souls (you may remember the game seeming to freeze for several seconds when you interacted with the machine--that was it creating the save) so what you do with the souls won't carry over, but everything else will. Dialogue options implying you don't know/remember Eder are for new players who didn't play the first game. When you get to the beach and he joins your party, check his equipment. You'll see he has a medallion, and it's item description should match his ending slide from the first game.
house2fly's post in Why is my Import Save called Lighthouse? was marked as the answer