[Aiwendil]

Lalwende wrote:

Firstly in the line descended from Durin there seems to be a peculiar kind of continuation with 'Durin the Deathless' reappearing several times to all intents and purposes. This makes me wonder what happens to these 'Durins' when they die. Do they go somewhere, to a Dwarven Halls of Mandos and then return?

The only really substantial discussion of this point, as far as I know, is found in HoMe XII, in "Last Writings".

It is possible that this false notion was in some ways connected with the various strange ideas which both Elves and Men had concerning the Dwarves, which were indeed largely derived from the Dwarves themselves. For the Dwarves asserted that the spirits of the Seven Fathers of their races were from time to time reborn in their kindreds. This was notably the case in the race of the Longbeards whose ultimate forefather was called Durin, a name which was taken at intervals by one of his descendants, but by no others but those in a direct line of descent from Durin I. Durin I, eldest of the Fathers, 'awoke' far back in the First Age (it is supposed, soon after the awakening of Men), but in the Second Age several other Durins had appeared as Kings of the Longbeards (Anfangrim). In the Third Age Durin VI was slain by a Balrog in 1980. It was prophesied (by the Dwarves), when Dain Ironfoot took the kingship in Third Age 2941 (after the Battle of Five Armies), that in his direct line there would one day appear a Durin VII - but he would be the last. Of these Durins the Dwarves reported that they retained memory of their former lives as Kings, as real, and yet naturally as incomplete, as if they had been consecutive years of life in one person.

Note that the reference to Durin's waking after the awakening of Men depends on the 'Myths Transformed' chronology.

This notion was almost immediately changed, however, for the second version of this text has:

. . . the reappearance, at long intervals, of the person of one of the Dwarf-fathers, in the lines of their kings - e.g. especially Durin - is not when examined probably one of rebirth, but of the preservation of the body of a former King Durin (say) to which at intervals his spirit would return. But the relations of the Dwarves to the Valar and especially to the Vala Aule are (as it seems) quite different from those of Elves and Men.

And there is a further note:

What effect would this have on the succession? Probably this 'return' would only occur when by some chance or other the reigning king had no son. The Dwarves were very unprolific and this no doubt happened fairly often.

Of course, that doesn't address the issue of where Dwarven spirits (Durin or otherwise) go after death.