: I'm not going to even try and explain it. I have no idea.
Admittedly, Balmung could be re-created without much continuity and style debate, since it's not too unique. But my theory about the Tain (which I posted before) is that its world is a dream world much like those of the Fetch and Myrkridia, and that it is linked to and bonded with the Tain, explaining why the Tain world beaks apart when the Tain does. This also means you could only forge one Tain.
Oh, and about the Sunhammer--maybe it was just MJ's sloppiness when creating Myth III, but the item struck me as rather cheesy, and cheesiness has no place in Myth.