Dagor Dagorath/Turin returning?

[Puddleglum]

Originally Posted by Galadriel55

he would consider himself fully free of this world, and, having no more purpose in it (as well as finding this satisfaction of achieving the purpose - inner peace?), he would not linger in it.

Welllll, technically, the Dagorath comes at the end of the world - so after it there is no more world to linger IN --- for anyone!

As for the actual changing of the nature of a being (edain to ainu), if that were actually contemplated by Tolkien (in the final story version), I think that could ONLY be accomplished by Eru, and that "IF" (a big "if") Eru chose in his wisdom to do so, he (and he alone) COULD do so.
Whether that would make for a satisfying storyline is a different question.

One part of the matter that intrigues me (i.e. of the story line where Turin "does" come back and slay Morgoth) is that Morgoth, in cursing Hurin's line and following Turin with such ferocity, was then actually training and raising up the tool of his own destruction. Building in Turin such a resolve that his Fea refused to leave Arda and remained in Mandos for the rest of Time - UNTIL the Dagorath and the coming of the end "when Melkor should return".
Oh the Irony!!

Morgoth, you would have been better off yourself had you left Turin alone and let him live out his life unmolested.