I don't think the sword is meant for killing a demon king, but something far greater.I bet the sword is a fake and there isn't a true hero, it's just there to discourage any "would be" heroes whose only conviction is that they will wield a powerful sword and that it's "their fate" to kill the demon king
Also I wonder how many generations has Frieren been clearing the demons away from the sword
No, I don't think that was the case. He certainly died first by a good while. But that doesn't mean he was older. Maybe the goddess kept Heiter alive long enough to raise Fern.wait, wasn't Himmel supposed to be a lot older than Heiter?
did the autor forgot about it?